US20050168445A1 - Optical detection system, device, and method utilizing optical matching - Google Patents
Optical detection system, device, and method utilizing optical matching Download PDFInfo
- Publication number
- US20050168445A1 US20050168445A1 US11/089,884 US8988405A US2005168445A1 US 20050168445 A1 US20050168445 A1 US 20050168445A1 US 8988405 A US8988405 A US 8988405A US 2005168445 A1 US2005168445 A1 US 2005168445A1
- Authority
- US
- United States
- Prior art keywords
- optical
- speckle
- image data
- image
- photosensor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
Images
Classifications
-
- G—PHYSICS
- G06—COMPUTING; CALCULATING OR COUNTING
- G06F—ELECTRIC DIGITAL DATA PROCESSING
- G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
- G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
- G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
- G06F3/0304—Detection arrangements using opto-electronic means
- G06F3/0317—Detection arrangements using opto-electronic means in co-operation with a patterned surface, e.g. absolute position or relative movement detection for an optical mouse or pen positioned with respect to a coded surface
Definitions
- the present invention relates to pointing devices for cursors on video display screens in a data processing environment. More particularly, the present invention relates to an optical system, device, and method for imaging a surface to perceive a displacement of the surface without having mechanically moving parts or without requiring a specially patterned surface.
- Pointing devices such as a mouse or a trackball, are well known peripheral devices in data processing environments. Pointing devices allow for cursor manipulation on a visual display screen of a personal computer or workstation, for example. Cursor manipulation includes actions such as rapid relocation of a cursor from one area of the display screen to another area or selecting an object on a display screen.
- a user controls the cursor by moving the electromechanical mouse over a reference surface, such as a rubber mouse pad so that the cursor moves on the display screen in a direction and a distance that is proportional to the movement of the electromechanical mouse.
- a reference surface such as a rubber mouse pad
- the conventional electromechanical mouse consisted of a mechanical approach where a ball is primarily located within the mouse housing and a portion of the ball is exposed to come in contact with the reference surface so that the ball may be rotated internally within the housing.
- the ball of the conventional electromechanical mouse contacts a pair of shaft encoders.
- the rotation of the ball rotates the shaft encoders, which include an encoding wheel that has multiple slits.
- a light emitting diode (“LED”), or similar light source is positioned on one side of the encoding wheel, while a phototransistor, or similar photosensor, is positioned opposite to the LED.
- LED light emitting diode
- the rotation of the encoding wheel results in a series of light pulses, from the LED shining through the slits, that are detected by the phototransistor.
- the rotation of the ball is converted to a digital representation which is then used to move the cursor on the display screen.
- the conventional electromechanical mouse is a relatively accurate device for cursor manipulation.
- the electromechanical mouse however, has drawbacks associated with many other devices that have mechanical parts. Namely, over time the mechanical components wear out, become dirty, or simply break down so that the cursor can no longer be accurately manipulated, if at all.
- An optical mouse reduces, and in some instances eliminates, the number of mechanical parts.
- a conventional optical mouse uses a lens to generate an image of a geometric pattern located on an optical reference pad.
- the conventional optical mouse uses a light beam to illuminate an optical reference pad having a special printed mirror geometric pattern.
- the geometric pattern is typically a grid of lines or dots that are illuminated by the light source and then focused by a lens on a light detector in the conventional optical mouse.
- the grids are made up of orthogonal lines with vertical and horizontal lines that are printed in different colors and so that when the grid is illuminated, the grid reflects light at different frequencies.
- the colors absorb light at different frequencies so that optical detectors of the optical mouse can differentiate between horizontal and vertical movement of the conventional optical mouse.
- the photodetector picks up a series of light-dark impulses that consist of reflections from the printed mirror surface and the grid lines and converts the impulses into square waves.
- a second LED and photodetector, mounted orthogonally to the first, is used to detect motion in an orthogonal direction.
- the conventional optical mouse counts the number of impulses created by its motion and converts the result into motion information for the cursor.
- the conventional optical mouse provides the advantage of reducing or eliminating the number of mechanical parts.
- the conventional optical mouse has several drawbacks.
- One problem with the conventional optical mouse is that it requires an optical pad as described above.
- a coherent light source was used with the conventional optical mouse.
- the coherent light source illuminated the surface directly below the mouse on most surfaces, except mirror-like surfaces.
- the use of a coherent light source produced more problems.
- speckles are a phenomenon in which light from a coherent source is scattered by a patterned surface, such as the grid, to generate a random-intensity distribution of light that gives the surface a granular appearance.
- speckles In the conventional coherent light optical mouse it is necessary to generate images of speckles to replace the optical pad.
- the imaging resolution is given by a photosensor pitch, e.g., the distance between two neighboring pixels or the periodicity, ⁇ , of the detector, a value that typically ranges from 10 micrometers to 500 micrometers. Elements in the image plane having a size smaller than this periodicity are not properly detected.
- a pattern is improperly detected by an imaging device when it is too small.
- the image is ambiguous if the pattern is smaller than the pixel size.
- speckles are generated through phase randomization of scattered coherent light, the speckle pattern has a defined size on average, but can exhibit local patterns not consistent with its average shape. Therefore, it is unavoidable for the system to be locally subjected to ambiguous or hard to interpret data, such as where a speckle count observed by the imaging system is small.
- An additional problem in conventional optical pointing devices is attaining a small displacement resolution without significantly increasing costs due to increased hardware complexities and increased computational loads.
- New images are acquired on a regular basis, at an acquisition rate allowing at least one common part of the image to be included in two successive snapshots, even at high speed.
- the present invention includes an optical detection system, device, and method for detection of motion of an optical pointing device relative to a surface.
- the system and method of the present invention includes a coherent light source, an optical sensing assembly, a cross-correlation module, and a microcontroller.
- the coherent light source for example, a laser diode, produces a coherent light beam that generates an illumination spot on a surface, or object plane, and is scattered off of the surface.
- the scattered light is directed towards, and received by, the optical sensing assembly.
- the optical sensing assembly includes one or more photosensor arrays and one or more optical elements.
- Each photosensor array of the plurality of photosensor arrays includes pixels of a particular size and a defined shape.
- the pixel is a single photosensitive element in the photosensor array.
- each optical element of the plurality of optical elements includes an artificially limited aperture.
- the received reflected illumination spot passes through the optical elements and forms speckle images on the photosensor, or image, plane.
- the optical sensing assembly is configured so that each artificially limited aperture is optically matched, either isotropically for a square pixel or anisotropically for other pixel shapes, to a corresponding photosensor array based on that photosensor array's pixel shape.
- Optical matching allows for the set of speckle images, having a varying speckle size, to have a single speckle cover at least one pixel of the photosensor array. Note that optical matching makes sure that the average size of a speckle image is larger than the pixel for both x and y directions.
- the pixel values from the speckle image that are received by the photosensor array provides an unambiguous speckle image data signal that is stored in a storage medium for further processing.
- the storage medium may be digital memory. If pixel values of the speckle images are captured and directly stored in voltage form, the storage medium may be an analog memory, such as a capacitor array, e.g., a bucket brigade device (“BBD”) or a charge coupled device (“CCD”).
- BBD bucket brigade device
- CCD charge coupled device
- the optical sensing assembly When there is movement of the optical mouse, the optical sensing assembly generates a new set of speckle images on the pixels of the photosensor arrays. For a displacement smaller than the illumination spot, the displacement of the surface translates into an equivalent speckle image displacement.
- the new unambiguous speckle image data signal generated by the photosensor arrays is captured in the storage medium.
- the new speckle image data signal and the previous speckle image data signal that are stored in the storage medium are then used to perform an image motion detection calculation, such as a cross-correlation analysis, using a cross-correlation module to determine the displacement of the two sets of speckle images.
- the calculated displacement corresponds to the movement of the optical pointing device.
- One cross-correlation analysis can occur when there is a multi-resolution image scheme.
- the cross-correlation analysis between the new speckle image data signal and the previous speckle image data signal is computed over a limited set of points.
- this set of points is all points in a low resolution image area plus a small range of points around the estimated displacement in a high resolution image area.
- the displacement related to the movement is determined by where a cross-correlation function of the cross-correlation analysis peaks.
- Another cross-correlation analysis can occur where there is a single resolution image scheme.
- the cross-correlation analysis between the new speckle image data signal and a reference, or previous, speckle image data signal is computed in one dimension—along a direction perpendicular to the elongated speckle images.
- the effects of lateral motion from the other direction is minimized because the speckles are elongated in that direction, therefore, producing little change in the image data signal as long as lateral displacement is smaller than the largest dimension of a pixel of a photosensor array.
- the one-dimensional cross-correlation analysis reduces power consumption because fewer calculations are required to determine displacement of the optical pointing device.
- a method of the claimed invention includes producing a coherent light beam and scattering the coherent light beam off of a surface.
- the scattered coherent light is received by an optical sensing assembly.
- the received scattered coherent light travels through a plurality of optical elements, where each optical element includes an artificially limited aperture that is matched with a photosensor array of a plurality of photosensor arrays.
- the speckle image generated through each optical element is passed onto an associated photosensor array on which each speckle has a size larger than the pixel size on average.
- the optically matched photosensor arrays and corresponding artificially limited aperture of the optical elements generate a set of unambiguous speckle image signals that is stored in a storage medium.
- a cross-correlation analysis is performed between the unambiguous image signal that is stored and a subsequent unambiguous image data signal that is generated at periodic instances when movement is detected within the system.
- Precision of determining a displacement is attained through the search of a cross-correlation function over a limited set of points, where the displacement is found at the coordinates where the cross-correlation function of the cross-correlation analysis peaks.
- the claimed invention advantageously provides an optical detection system that detects movement of an optical pointing device relative to a surface that can generate speckle images.
- the claimed invention includes an optical sensing assembly having one or more optical elements and one or more artificially limited apertures that are optically matched to a plurality of photosensor arrays that generate an unambiguous image data signal from a speckle image formed from a diffusely scattered coherent light beam.
- the unambiguous image data signal is used to detect movements with greater precision without requiring greater system resources such as computational power and/or illumination power.
- the claimed invention overcomes the adverse affects of position tolerance by allocating additional identical optical elements for each photosensor array so that the overlapping images of the illumination spot are generated to adequately cover each photosensor array even with worst case misalignment considerations.
- FIG. 1 is a diagram of an operating environment in accordance with the present invention.
- FIG. 2 a is an external diagram of an optical pointing device in accordance with the present invention.
- FIG. 2 b is a partial internal diagram of an optical pointing device in accordance with the present invention.
- FIG. 3 is a diagram illustrating generally an optical sensing assembly in accordance with the present invention.
- FIG. 4 a is a diagram illustrating a cross-sectional view of the optical sensing assembly in accordance with the present invention.
- FIG. 4 b is a symbolic view illustrating a speckle field image on a photosensor array in accordance with the present invention.
- FIGS. 4 c and 4 d are symbolic views illustrating an ambiguous speckle image verses an unambiguous speckle image.
- FIG. 5 a is a diagram of an optical sensing assembly having multiple optical elements for each photosensor array in accordance with the present invention.
- FIG. 5 b is a symbolic view illustrating multi-resolution capabilities of the optical sensing assembly in accordance with the present invention.
- FIG. 6 is a block diagram illustrating a multi-resolution displacement detection system in accordance with the present invention.
- FIG. 7 a is a flow diagram illustrating operation of the multi-resolution displacement detection system in accordance with the present invention.
- FIG. 7 b is a flow diagram illustrating operation of a 2-D cross-correlation module and microcontroller of the multi-resolution displacement detection system in accordance with the present invention.
- FIG. 8 is a symbolic view illustrating the artificially limited and anisotropic aperture in accordance with the present invention.
- FIG. 9 is a block diagram illustrating an anisotropic motion detection system in accordance with the present invention.
- FIG. 10 is a flow diagram illustrating operation of a 1-D cross-correlation module in accordance with the present invention.
- FIG. 1 is a diagram of an embodiment of an operating environment 100 in accordance with the present invention.
- the operating environment 100 includes an optical pointing device 110 , a surface 120 , and a computer system 130 .
- the surface 120 may be any surface that can diffusely reflect light, such as a table or desk, for example.
- the computer system 130 may be a conventional computer system such as an IBM PCTM, Apple MacIntoshTM, Sun SPARCStationTM, or the like.
- the computer system 130 includes a processor, a memory, a display screen, and an input port for a pointing device.
- the optical pointing device 110 is coupled to the input port of the computer system 130 . It is noted that although the optical pointing device 110 may be coupled to the input port of the computer system 130 using a wire connection such as an optical pointing device cable 140 , other coupling connections such as infrared or radio frequency control may also be applicable.
- FIG. 2 a is an external diagram of the optical pointing device 130 in accordance with the present invention.
- the optical pointing device 130 includes a shell housing 210 having an underside 220 .
- the underside 220 includes a coherent light emission area 230 for emission of a coherent light source 250 and a light detection area 240 for an optical sensing assembly 260 .
- the coherent light source 250 is a laser diode.
- the coherent light source 250 may also be another coherent light emitting source or may be a partially coherent light emitting source, in which the coherent light component is used by the optical pointing device 130 .
- the laser diode comprises a light emitting die and a transparent package that performs collimation or beam shaping.
- the laser diode comprises a light emitting die and an independent beam shaping optical element to perform collimation or other beam shaping.
- the underside 220 of the optical detection system 110 is placed on or in close proximity to the surface 120 during operation.
- FIG. 2 b is a partial internal diagram of the optical pointing device 130 in accordance with the present invention.
- the optical pointing device 130 includes the coherent light source 250 and the optical sensing assembly 260 .
- the coherent light source 250 is directed such that a coherent light beam would be emitted through the coherent light emission area 230 towards the surface 120 .
- the coherent light beam from the coherent light source 250 is then partially reflected off of the surface 120 toward the light detection area 240 , and more specifically, the optical sensing assembly 260 .
- the coherent light beam is a collimated beam 305 .
- a quasi-collimated beam is used, where a certain degree of convergence or divergence is applied.
- the coherent light emission area 230 and the light detection area 240 are collectively a single area.
- FIG. 3 is a diagram illustrating the optical sensing assembly 260 in accordance with the present invention.
- the optical sensing assembly 260 comprises one or more optical elements 310 , one or more photosensor arrays 320 , a transparent printed circuit board 340 , and molded fittings 350 .
- the optical sensing assembly 260 is described with two optical elements 310 a , 310 b (generally referenced as 310 ) and two photosensor arrays 320 a , 320 b (generally referenced as 320 ).
- the transparent printed circuit board 340 includes a first side 345 a and a second side 345 b .
- the first side 345 a includes a microlens array 360 , which is further discussed below.
- an opaque printed circuit board may be used, however, it must be fitted with openings to allow light to pass through to the photosensor arrays 320 a , 320 b .
- the second side 345 b which is opposite the first side 345 a , includes the photosensor arrays 320 a , 320 b , with the sensitive side facing towards the microlens array 360 .
- Each optical element 310 a , 310 b includes a lens 315 a , 315 b (generally referenced as 315 ) having a focal length, f, an artificially limited aperture 330 a , 330 b (generally referenced as 330 ), AP, and molded fittings 350 .
- the focal length, f is between 1 mm and 5 mm, for example.
- each artificially limited aperture 330 a , 330 b , AP has an aperture half-diameter, wp, and is integrated with its respective lens 315 a , 315 b , for example, by attaching an aperture mask onto each lens 315 a , 315 b .
- the molded fittings 350 are coupled to the lens 315 a , 315 b on edges opposite to each other.
- the molded fittings 350 may be integrated with each lens 315 a , 315 b to form a single integrated optical piece.
- the optical elements 310 a , 310 b are arranged as a single, refractive microlens array 360 .
- the optical elements 310 a , 310 b may be arranged as a single diffractive microlens array 360 , in which case the aperture function is directly combined with the lens function.
- the microlens array 360 includes integrated aperture openings for each optical element 310 a , 310 b .
- the microlens array 360 may include the beam shaping optical element.
- Each optical element 310 a , 310 b is positioned and coupled on the microlens array 360 so that each artificially limited aperture is centered about its respective aperture opening.
- the assembled microlens array 360 is coupled to the first side 345 a of the transparent printed circuit board 340 of the optical sensing assembly 260 .
- Each photosensor array 320 a , 320 b is comprised of one or more pixels 420 , further illustrated as individual squares in FIG. 4 b .
- a pixel 420 is a single photosensitive element in the photosensor array 320 a , 320 b that can detect a light intensity.
- the number of pixels 420 can range from 4 by 4 to 30 by 30, for example.
- each pixel 420 has a defined isotropic size and shape where the size may be defined as the distance between two neighboring pixels 420 as opposed to the size of the light sensitive area of the pixel.
- the photosensor arrays 320 a , 320 b capture image data by generating image data signals based on pixel values generated as a result of an image covering the pixels 420 .
- the distance between two successive pixels 420 is a photosensor pitch, e.g., the periodicity, ⁇ .
- the photosensor pitch defines the size of a pixel and describes the resolution of the system, e.g., the smallest discernible element in the image plane.
- the microlens array 360 and the photosensor arrays 320 a , 320 b are geometrically aligned so that an image produced on each photosensor array 320 a , 320 b is the image of a common, yet unique, illuminated spot 390 obtained through a spot fan-out.
- Spot fan-out is when the image of the same illuminated spot 390 is received at different photosensor arrays within the optical sensing assembly 260 after passing through the associated optical element 310 .
- spot fan-out results when the center 390 a ′ of the spot 390 , the center 390 b ′ of a lens 315 a , 315 b , the center 390 c ′ of an aperture 330 a , 330 b , and the center 390 d ′ of a photosensor array 320 a , 320 b are all aligned on a straight line.
- the collimated beam 305 from the coherent light source 250 can be of a minimal size, about the size of the largest photosensor array.
- the minimal size of the collimated beam 305 produces a high intensity spot 390 that is easier to detect reliably, while reducing power consumption within the system through the use of a low illumination coherent light source 250 .
- This is in contrast to conventional systems where the collimated beam must be wide enough so that the image of an illumination spot covers a surface large enough to include all the photosensor arrays, thus requiring a coherent light source that consumes greater power.
- the spot fan-out feature may also be used to generate multiple images by scattering, or diffusely reflecting, the same illuminated spot 390 through the optical elements 310 on one or more photosensor arrays 320 a , 320 b , either overlapping each other or not, to illuminate the photosensor array 320 a , 320 b with a sum of small images of the spot.
- FIG. 4 a is a diagram illustrating a cross-sectional view of the optical sensing assembly in an optical detection system in accordance with the present invention.
- the optical sensing assembly 260 is shown to include the microlens array 360 having the optical elements 310 a , 310 b , including the lenses 315 a , 315 b and the artificially limited apertures 330 a , 330 b , the photosensor arrays 320 a , 320 b , and the transparent printed circuit board 340 .
- the optical sensing assembly 260 is also shown to include an air or a transparent adhesive 342 layer between the microlens array 360 and the transparent printed circuit board 340 .
- the photosensor arrays 320 a , 320 b reside on a single silicon die layer 344 .
- the silicon die is mounted on the printed circuit board 340 using, for example, a flip-chip mounting technology.
- the microlens array 360 is a diffractive microlens array. A diffractive microlens array allows for an artificially limited aperture to be included by design in the diffractive pattern together with the lens function so that the aperture is aligned with the lens.
- the collimated beam 305 from a coherent light source 250 is directed towards a surface 120 .
- the collimated beam 305 produces the illumination spot 390 , including a spot center 390 a ′, on the surface 120 .
- the surface 120 scatters, i.e., diffusely reflects, the collimated beam 305 at the location of the spot 390 a towards the lenses 315 of the optical sensing assembly 260 .
- the scattered light 305 ′ passes through the central point, f′, of the lenses 315 a , 315 b , through the artificially limited apertures 330 a , 330 b , and to the photosensor arrays 320 a , 320 b , in a fan-out manner, as described above.
- the scattered light 305 ′ that passes through the optical elements 310 a , 310 b generates speckle images on the respective photosensor arrays 320 a , 320 b as is further described below.
- a speckle image may be defined as a phenomenon in which a light beam from a highly coherent source is scattered off of a surface or medium to generate a random intensity distribution of light that give the surface or medium a granular appearance.
- FIG. 4 b illustrates an example of a speckle field image that appears on the photosensor arrays 320 a , 320 b in accordance with the present invention.
- the speckle field image includes one or more speckles 410 .
- Each photosensor array 320 a , 320 b has pixels 420 that are isotropic, i.e., of the same size in both the x-direction and the y-direction (e.g., a square) relative to an x-y plane, with respect to other pixels of the other photosensor array.
- Each photosensor array 320 a , 320 b is geometrically aligned with an associated optical element 310 a , 310 b , as described above in FIG. 3 , as well as the illumination spot 390 location, so that the spot fan-out feature is applicable.
- FIG. 4 b A symbolic view of the artificially limited aperture 330 a , 330 b is shown in FIG. 4 b as a first dotted outline 330 a ′, 330 b ′ on each photosensor array 320 a , 320 b .
- the second dotted outline 390 ′′ illustrates the size of the image of the illumination spot 390 relative to the photosensor array 320 a , 320 b .
- the dark spots illustrate speckle images 410 that appear on the photosensor arrays 320 a , 320 b.
- the speckle field image that is received by the photosensor arrays 320 a , 320 b appears when the diffusely reflected light from the illumination spot 390 is received and passed through the optical element 310 a , 310 b having the artificially limited aperture 330 a , 330 b that is associated with the respective photosensor array 320 a , 320 b .
- the speckle field image is based on the scattered light 305 ′ from the reflected illumination spot 390 and is received and passed through the optical sensing assembly 260 .
- the speckle field image is unique to each photosensor array 320 a , 320 b because of the angle of reflection of the collimated beam 305 that is diffusely reflected from the illumination spot 390 a ′ off of the surface 120 , through the optical elements 310 a , 310 b , and fanned out onto the photosensor arrays 320 a , 320 b .
- the speckle field image received by the photosensor arrays 320 a , 320 b are used to generate unambiguous speckle image data signals that advantageously provide a complete representation of a speckle image 410 .
- FIGS. 4 c and 4 d provide an example illustrating an ambiguous speckle image versus and unambiguous speckle image.
- an unambiguous speckle image data signal is obtained when it is known that the signal delivered by the pixels 420 capturing the speckle 410 will see at least some of the output value differ if a small displacement is applied to the surface of the speckle 410 .
- the speckle 410 is shown moving from point A to point B on a photosensor array 320 of an optical pointing device.
- the speckle displacement is a result of movement of an optical pointing device.
- the output of a pixel 420 of the photosensor array 320 is the sum of the light that impinges on the pixel 420 and because this sum is identical for both positions of the speckle 410 , despite the new location of the speckle 410 , there is only one set of values for calculating displacement.
- the speckle 410 is shown moving from point C to point D.
- the speckle translation is a result of translation of the optical pointing device 130 .
- the speckle 410 in FIG. 4 d produces an image signal that is unambiguous.
- the unambiguous speckle image data signal allows for reconstruction of the speckle image 410 from the pixels 420 as further described below.
- the unambiguous data signal provides unambiguous and reliable motion detection when applying a motion detection analysis, such as a cross-correlation analysis, to the speckle image data signal.
- the speckle images 410 are captured as speckle image data by the photosensor arrays 320 a , 320 b and will be used to determine displacement, or motion, of the optical pointing device 110 as will be further described below.
- the unambiguous speckle image data signals obtained from the speckle image 410 illustrated in FIG. 4 b are obtained through optical matching.
- Optical matching describes a property of an optoelectronic system, such as in an optical sensing assembly, matching a relevant feature of the optical subsystem to a relevant feature of the electronic photosensor array subsystem.
- optical matching is a result of artificially limiting the optical aperture 330 for a given illumination wavelength so as to match the periodicity, or pitch, A, of the photosensor array 320 .
- the optical matching relationship becomes AP ⁇ (2/ ⁇ )( ⁇ / ⁇ ), where AP is the aperture, ⁇ is the light wavelength, and ⁇ is the periodicity, or pitch, of the photosensor array 320 .
- the optical matching relationship with reference to an x-y plane becomes APx ⁇ (2/ ⁇ )( ⁇ / ⁇ x) for an x-direction and APy ⁇ (2/ ⁇ )( ⁇ / ⁇ y) for a y-direction.
- the pitch, ⁇ is the pixel 420 length in the x-direction and the interpixel spacing for the y-direction.
- the pitch is the pixel length in the y-direction and the interpixel spacing for the x-direction.
- the average diameter of a speckle in the speckle image 410 is larger than the pixel 420 size, where size refers to the pitch, ⁇ .
- size refers to the pitch, ⁇ .
- optical matching is achieved when the average speckle diameter along the x-direction and the y-direction, respectively, are larger than the size of the pixel 420 , along both the x-direction and the y-direction, respectively.
- Optical matching suppresses the occurrences of an ambiguous sample set of speckle image data signals generated by speckles 410 that are smaller than the pixel 420 size.
- speckles 410 are larger than a single pixel 420 on average which makes motion detection from successive sets of speckle image data signals reliable.
- difficulty arises from speckles 410 that are smaller than the pixel 420 size that produce image data signals that may not vary when a small displacement is applied to them.
- optical matching is obtained through artificially limiting the aperture, AP, 330 a , 330 b of each optical element 310 a , 310 b .
- Optical matching is defined for numerical apertures that are below a threshold value, that is AP ⁇ (2/ ⁇ ) ⁇ ( ⁇ / ⁇ ).
- a photosensor array having a pitch of 40 micrometers that is illuminated with a 900 nanometer coherent light source having an AP artificially limited to 0.014 can generate an unambiguous speckle image data signal from the speckle image 410 .
- the unambiguous image data signal is referred to as a fully resolved data signal and allows for a reliable cross-correlation analysis for determining displacement.
- a fully resolved data signal describes a data signal that allows a faithful reproduction of the image covering the photosensor array 320 when the speckle image data signal was generated.
- a fully resolved data signal precludes speckles 410 smaller than a pixel 420 size since it is not known from the signal if one or more speckles were covering the pixel 420 .
- Successive speckle images obtained from an optically matched optical sensing assembly allow for a cross-correlation analysis that provides a displacement value by looking for the peak of the cross-correlation function.
- the artificially limited apertures 330 a , 330 b of at least one optical element 310 a , 310 b is associated with at least one photosensor array 320 a , 320 b that has a matched resolution so that a speckle image 410 includes a speckle average size covering at least one pixel 420 of the photosensor array 320 a , 320 b .
- the optical elements 310 a , 310 b have artificially limited apertures 330 a , 330 b that are matched with the photosensor arrays 320 a , 320 b having matched resolution to reduce the impact of ambiguous data due to statistical fluctuations.
- the optical assembly 260 in accordance with the present invention may use multiple optical elements 310 a - 1 - 310 a - n , for example five optical elements 310 a - 1 - 310 a - 5 , each having an artificially limited aperture 330 , for each photosensor array 320 .
- This configuration alleviates the affects of position tolerance, or misalignment.
- the multiple optical elements 310 a - 1 to 310 a - 5 provide overlapping images derived from the scattered illumination spot 390 passing through each so that the matched photosensor array 320 a is adequately covered with light.
- the pixels 420 of the photosensor array 320 a can detect the image of the illumination spot 390 even with a worst case misalignment of the optical elements 310 and the photosensor arrays 320 a because the photosensor array 320 a is entirely exposed by a speckle image field generated through any of the multiple optical elements 310 a - 1 to 310 a - 5 .
- FIG. 5 a diagramatically illustrates the optical assembly 260 configuration that can be used in either a single resolution or multi-resolution environment.
- a multi-resolution environment there will be at least two sets of optical elements 310 configured as described above.
- FIG. 5 b illustrates a multi-resolution environment through a symbolic view of speckle images 410 in accordance with the present invention.
- the optical sensing assembly 260 includes a multi-element setup.
- different optical elements 310 a , 310 b each having a different artificially limited aperture, AP, 330 a , 330 b and different photosensor arrays 320 a , 320 b , each having a different pitch, ⁇ , are used to capture a plurality of speckle images 410 .
- the different artificially limited apertures 330 a , 330 b create speckle images 410 of different sizes. For example, a large aperture creates a smaller speckle image as illustrated with the second photosensor 320 b . By contrast, a small aperture creates a larger speckle image as illustrated with the first photosensor 320 a .
- the photosensor arrays 320 a , 320 b capture these speckle images 410 .
- each of the optical elements 310 a , 310 b must be optically matched with one of the photosensor arrays 320 a , 320 b in the optical sensing assembly 260 .
- each optical element 310 a , 310 b is associated with a photosensor array 320 a , 320 b by matching the speckle image size resulting from the artificially limited aperture 330 a , 330 b with a proper photosensor pitch so that an average diameter of a speckle is larger than one pixel 420 .
- an optical element 310 a having a large aperture 330 a is matched with a photosensor array 320 a having smaller pixels and thus, a smaller pitch, ⁇ , as shown in FIG. 5 b , to produce a high resolution speckle image data signal.
- an optical element 310 b having a small aperture 330 b is matched with a photosensor array 320 b having larger pixels and thus, larger pitch, ⁇ , between pixels, as shown in FIG. 5 b , to produce a low resolution speckle image data signal.
- the resulting plurality of speckle images 410 of different sizes and resolution among different photosensor arrays 320 a , 320 b forms a multi-resolution set of images that is a result of the fan-out from the diffusely reflected illumination spot 390 after passing through the optical elements 310 as described above.
- the multi-resolution architecture requires less power consumption as computational loads are significantly decreased.
- FIG. 6 is a block diagram illustrating the multi-resolution displacement detection system 605 , including the optical sensing assembly 260 , in accordance with the present invention.
- the multi-resolution detection system 605 obtains the multi-resolution architecture of speckle images as discussed above and determines a two-dimensional displacement of the optical pointing device 110 as further described below.
- the multi-resolution detection system 605 includes the coherent light source 250 , the optical sensing assembly 260 , a first low-resolution data signal line 610 , a second high-resolution image data signal line 615 , a two-dimensional (“2-D”) y-direction cross-correlation module 620 , a two-dimensional (“2-D”) x-direction cross-correlation module 625 , a y-control line 630 , a x-control line 635 , a y-change line 640 , a x-change line 645 , a y-acknowledge line 637 , a x-acknowledge line 647 , a y-strobe line 642 , a x-strobe line 652 , a microcontroller 650 , a first and a second microcontroller output line 655 a , 655 b , a line interface module 660 , a first line interface output line 665 a , and
- the y-change line 640 and the x-change line 645 are in one embodiment 8-bit bus lines so that the signals along those lines, ⁇ y signal and ⁇ x signal, respectively, can be any integer between ⁇ 127 and +127.
- the 2-D y-direction and the 2-D x-direction cross-correlation modules 620 , 625 include a memory, or storage, element. In an alternative embodiment, the 2-D y-direction and the 2-D x-direction cross-correlation modules 620 , 625 may be substituted with a general motion detection system.
- a first photosensor 320 a and a second photosensor 320 b of the optical sensing assembly 260 are coupled to both the 2-D y-direction cross-correlation module 620 and the 2-D x-direction cross-correlation module 625 through the first and the second image data signal line 610 , 615 , respectively.
- the 2-D y-direction cross-correlation module 620 is coupled to the microcontroller 650 through the y-control line 630 , the y-change line 640 , the y-acknowledge line 637 , and the y-strobe line 642 .
- the 2-D x-direction cross-correlation module 625 is coupled to the microcontroller 650 through the x-control line 635 , the x-change line 645 , the x-acknowledge line 647 , and the x-strobe line 652 .
- the microcontroller 650 is coupled to the coherent light source 250 , such as a laser diode.
- the microcontroller 650 is also coupled to the line interface 660 through the first and the second microcontroller output lines 655 a , 655 b .
- the output from the line interface 660 is a standard communication protocol, such as a serial port communication protocol or a universal serial bus protocol, for example.
- photosensor arrays 320 , microcontroller 650 , and cross-correlation modules 620 , 625 may be integrated on a single complementary metal oxide semiconductor integrated circuit using a conventional digital signal processing (“DSP”) core.
- DSP digital signal processing
- these elements may be built using discrete integrated circuits such as a microcontroller or DSP chips, for example.
- FIG. 7 a illustrates the operation of the multi-resolution displacement detection system 605 in accordance with the preferred embodiment of the present invention.
- the process starts 705 when the collimated beam 305 is produced 710 from the coherent light source 250 of the optical pointing device 130 .
- the collimated beam 305 is scattered 715 off of the surface 120 .
- the scattered light is received 720 by the optical sensing assembly 260 so that it is fanned-out 725 through the lenses 315 a , 315 b and artificially limited apertures 330 a , 330 b of the optical elements 310 a , 310 b to ultimately generate a speckle image on the appropriate photosensor array 320 a , 320 b .
- the optical elements 310 a , 310 b having the artificially limited apertures 330 a , 330 b are optically matched with an associated photosensor array 320 a , 320 b so that the reflected illumination spot passing 725 through the artificially limited apertures 330 a , 330 b produces speckle images on the photosensor arrays 320 a , 320 b that have an average diameter at least equal to one pixel 420 of the associated photosensor array 320 a , 320 b.
- an unambiguous image data signal is generated 730 .
- the image data signal is the collection of all pixel values that are generated by the photosensor array 320 a , 320 b .
- a speckle image is received, a conversion from a light intensity of the speckle image to a voltage value which represents the pixel value is accomplished through a conventional charge coupled device (“CCD”) or a photodiode system.
- An image data signal is then generated 730 as the sequential readout of all the pixel values, for example.
- a pixel clock signal (not shown) is used for pixel value synchronization to indicate when the image data signal should be acquired as the pixel values are sequentially output from the photosensor arrays 320 a , 320 b.
- the newly received, or current, unambiguous image data signal is stored 735 in the memory, or storage medium, of the cross-correlation modules 620 , 625 .
- the 2-D y-direction cross-correlation module 620 and the 2-D x-direction cross-correlation module 625 perform a cross-correlation analysis with unambiguous image data signals for the y-direction and the x-direction, respectively.
- the 2-D x-direction and 2-D y-direction cross-correlation modules 620 , 625 are typically implemented using a digital signal processor core. Each cross-correlation module 620 , 625 performs a cross-correlation analysis only over a limited set of image signal points, which comprises the search range, by calculating a cross-correlation function and determining the peak value of the function by following an iterative search path.
- Cross-correlation is a measure of the similarity between a reference image and an unknown image. For example, a large cross-correlation may mean there is a high degree of similarity between the reference image and the unknown image.
- a cross-correlation function provides the same measure of similarity, but computed for the reference image and the unknown image to which a displacement, a shift of (m, n), has been applied. The shift (m, n) provides an argument for the cross-correlation function.
- the peaks of the cross-correlation function provide the points, ⁇ x and ⁇ y, respectively, that determine the two-dimensional displacement of a speckle image that occurred since the last refresh, e.g., when the current reference set of image data signals was transferred from the current image in the memory of the 2-D y-direction and 2-D x-direction cross-correlation modules 620 , 625 .
- Displacement, ⁇ x and ⁇ y, respectively, is transferred as a signal from the x-direction cross correlation module 625 and the y-direction cross correlation module 620 , respectively, to the microcontroller 650 through the y-change and x-change lines 640 , 645 .
- the 2-D x-direction and 2-D y-direction cross-correlation modules 625 , 620 perform a two-dimensional cross-correlation analysis because a speckle image appears in both the x-direction and the y-direction on each photosensor array 320 a , 320 b .
- the 2-D x-direction and 2-D y-direction cross-correlation modules 625 , 620 have a different reference image data signal for cross-correlation computation depending on the detected displacement over an x- or a y-direction.
- the iterative search path cross-correlation analysis significantly reduces the number of operations when compared to an exhaustive search by conducting the search only over a limited search range.
- multi-resolution displacement detection includes the 2-D x-direction and 2-D y-direction cross-correlation modules 625 , 620 performing the cross-correlation analysis that is separately dedicated to the x-direction and the y-direction, while the optical sensing assembly 260 is common for both directions.
- FIG. 7 b ( 1 - 3 ) is a flow diagram illustrating operation of the 2-D cross-correlation modules 625 , 620 and the microcontroller 650 in accordance with the present invention. For purposes of simplicity, the flow diagram will be discussed with respect to the 2-D x-direction cross-correlation module 625 and it is understood that similar principles apply for the 2-D y-direction cross-correlation module 620 .
- a new set of image data signals for low-resolution, NewL(x, y), and for high-resolution, NewH(x, y), is acquired and stored into a memory.
- the memory stores two reference sets of image data signals, one for the x-direction and one for the y-direction, both of which are obtained from the previously acquired set of image data signals for low resolution, RefL 1 (x, y), and for high-resolution, RefH 1 (x, y).
- the 2-D x-direction and 2-D y-direction cross-correlation modules 625 , 620 of the multi-resolution displacement detection system 60 compute the cross-correlation function between the new set of image data signals and the corresponding reference set of image signals for both the x-direction and the y-direction. For example, at the start 770 of operation, low resolution data signals (from a first photosensor array 320 a , for example) and high resolution data signals (from a second photosensor array 320 b , for example) are read 772 from the photosensor arrays 320 a , 320 b . The data signals are converted 774 into digital values and stored 776 in memory as equivalent images, NewL(x, y) and NewH(x, y), to those captured on the photosensor arrays 320 a , 320 b.
- a low resolution cross-correlation analysis (RL(x, y)) is computed 778 , where (m, n) ⁇ [1 . . . Mx, 1 . . . My] and Mx and My are the number of pixels on the low resolution photosensor 320 a along the x-direction and the y-direction.
- a value for m 1 is forwarded 788 to the microcontroller 650 as a value ⁇ x through the x-change line 645 and the signal strobe_x is activated 790 by the x-direction cross correlation module 625 .
- the system determines 792 whether the microcontroller 650 activated an acknowledge_x signal.
- the acknowledge_x signal is sent to the 2-D x-direction cross correlation module 625 .
- the strobe_x signal is deactivated 800 . If control_x is not activated, the system directly deactivates 800 the strobe_x signal.
- the refresh includes transferring the current image data signal set into the reference image data signal set upon activation of the x-control 635 or y-control 630 by the microcontroller 650 using a technique as further described below.
- This technique is shown to effectively reduce any loss of sensitivity for low speed displacements either in the x-direction or the y-direction of an x-y plane while ensuring that the reference set of image signals is at least partly correlated with the new image set.
- the present invention beneficially eliminates a “snapping” effect and provides greater precision for determining displacement.
- the new set of image signals becomes the reference set of image signals for the x-direction, and similarly for the y-direction, for use with the next set of image signal.
- the transfer of the new set of image data signals into the reference set of image memory in the x-direction and y-direction cross correlation modules 625 , 620 is done upon activation of x_control or y_control signals, respectively, by the microcontroller 650 .
- the reference set of image signals is left unchanged, e.g., the x_control or y_control signals are not activated, for the particular direction unless the cumulative displacement, x_total and y_total, respectively, detected in the remaining direction corresponds to a sizable fraction, for example one-fourth, of the photosensor array. In such instances a refresh of the reference set of image data signals is performed using the current new set of image data signals.
- the microcontroller 650 activates the x_control signal along the x-control line 635 when the microcontroller 650 detects non-zero displacement along an x-direction, or when the cumulative displacement, y_total, since the last x-direction refresh along the y-direction is above a predetermined value, y_limit, such as an effective displacement equivalent to about one-fourth of the physical dimension of the photosensor array 320 .
- Activation of the x_control signal along the x-control line 635 means that the new set of image data signals become the reference set of image data signals for the next set of image data signals.
- the 2-D x-direction cross-correlation module 625 transfers the content of the memory, or portion thereof, that stores the new set of image data signals to the memory, or portion thereof, that stores the reference set of image data signals.
- the microcontroller 650 acquires the displacement, ⁇ x, as calculated by the 2-D x-direction cross-correlation module 625 .
- the acquired value of the displacement, ⁇ x is the computed displacement since the last refresh, i.e., the change in the reference image data signal.
- the microcontroller 650 then keeps a cumulative displacement, x_total, that is equal to the current x_total value plus the displacement, ⁇ x.
- the microcontroller 650 transmits x_total to the computer system 130 through the line interface 660 using a communication protocol such as a serial port communication protocol, universal serial bus communication protocol, or an IBM PS2TM mouse port communication protocol, for example.
- a communication protocol such as a serial port communication protocol, universal serial bus communication protocol, or an IBM PS2TM mouse port communication protocol, for example.
- the cross-correlation analysis can be iteratively applied to even higher resolution until a desired precision of displacement is reached.
- the number of operations that is, the number of cross-correlation function evaluations, needed to reach a desired precision is reduced significantly by searching the cross-correlation function only over a limited number of points by following the iterative search path.
- the optical elements may include artificially limited anisotropic apertures that are optically matched with associated photosensor arrays having a pitch, or periodicity, ⁇ , that is different for the x-direction and the y-direction so that a one-dimensional cross-correlation analysis may be performed.
- FIG. 8 is a symbolic view illustrating speckles captured on photosensor arrays 320 having a pitch that is different in the x-direction versus the y-direction and which are optically matched with an associated optical element having the artificially limited anisotropic aperture in accordance with the present invention.
- each photosensor array 320 is comprised of M adjacent rectangular pixels 420 having a rectangular pixel shape of aspect ratio, N, where N is the ratio of the pixel length over the pixel width.
- N is the ratio of the pixel length over the pixel width.
- FIG. 9 is a block diagram illustrating an anisotropic displacement detection system 905 in accordance with the present invention. Similar to the multi-resolution displacement detection system 605 in FIG. 6 , the anisotropic optical displacement detection system 905 includes the coherent light source 250 , the optical sensing assembly 260 , a first image data signal line 610 , a second image data signal line 615 , a 1-dimensional (“1-D”) y-direction cross-correlation module 920 , a 1-dimensional (“1-D”) x-direction cross-correlation module 925 , the y-control line 630 , the x-control line 635 , the y-change line 640 , the x-change line 645 , the y-acknowledge line 637 , the x-acknowledge line 647 , the y-strobe line 642 , the x-strobe line 652 , the microcontroller 650 , the first and the second microcontroller output line 655 a ,
- a first photosensor 320 a and a second photosensor 320 b of the optical sensing assembly 260 are respectively coupled to the 1-D y-direction cross-correlation module 920 and the 1-D x-direction cross-correlation module 925 respectively through the first and the second image data signal line 610 , 615 .
- the 1-D y-direction cross-correlation module 920 is coupled to the microcontroller 650 through the y-control line 630 , the y-change line 640 , the y-acknowledge line 637 , and the y-strobe line 642 .
- the 1-D x-direction cross-correlation module 925 is coupled to the microcontroller 650 through the x-control line 635 , the x-change line 645 , the x-acknowledge line 647 , and the x-strobe line 652 .
- the microcontroller 650 is coupled to the coherent light source 250 , such as a laser diode.
- the microcontroller 650 is also coupled to the line interface 660 through the first and the second microcontroller output lines 655 a , 655 b.
- the optical pointing device 130 of the present invention having an anisotropic displacement detection system produces a collimated beam 305 from the coherent light source 250 .
- the collimated beam 305 is diffusely reflected, i.e., scattered, off of the surface 120 .
- the scattered light is received by the optical sensing assembly 260 so that it is fanned-out through the lenses 315 a , 315 b and artificially limited anisotropic apertures 330 a , 330 b of the optical elements 310 a , 310 b to generate speckle images on the associated photosensor arrays 320 a , 320 b.
- the optical elements 310 having the artificially limited anisotropic apertures 330 a , 330 b are optically matched with an associated photosensor array 320 a , 320 b , having (M ⁇ 1) and (1 ⁇ M) pixels respectively, and having an aspect ratio of N.
- the aspect ratio, N is an elongation factor comprising the average speckle length over the average speckle width.
- Optical matching in such instances implies that the ratio of the long aperture to the small aperture is also N.
- the number of elongated pixels, M is at least two and is made equal to N, which yields an overall square photosensor array 320 .
- the speckle images generated by the artificially limited anisotropic apertures 330 a , 330 b comprise elongated speckles on the associated photosensor arrays 320 a , 320 b.
- an unambiguous image data signal is generated because a single elongated speckle will cover on average a single elongated pixel.
- the light intensity of a speckle image captured on a photosensor array 320 a , 320 b is converted to a voltage value representing a pixel value.
- the voltage, or pixel, value represents the intensity of the light applied to each pixel 420 and is based on a conventional charge coupled device, a photogate system, or a photodiode.
- the image data signal that is produced is an unambiguous image data signal that is a sequential readout of all the pixel values, for example. It is noted that although a pixel clock is not shown, it is present for pixel value synchronization to indicate when the image data signal should be acquired as pixel values are sequentially output from the photosensor arrays 320 a , 320 b.
- the unambiguous image data signal is stored in the memory, or storage medium, cross-correlation module 920 , 925 .
- the 1-D y-direction cross-correlation module 920 and the 1-D x-direction cross-correlation module 925 perform a cross-correlation analysis with unambiguous image data signals for the y-direction and the x-direction, respectively.
- the anisotropic configuration performs a cross-correlation analysis in one dimension—along the direction perpendicular to the elongated speckle images.
- the effects of lateral motion from the other direction is minimized because the speckles are elongated in that direction, thus, producing little change in the image data signal as long as lateral displacement is smaller than about one-fourth of the largest dimension of a pixel 420 .
- the use of a one dimensional cross-correlation analysis produces significant power savings because computations to determine a displacement occur in only one dimension and therefore, further reduce the number of operations required to determine the displacement of the optical pointing device 130 .
- FIG. 10 is a flow diagram illustrating a 1-D cross-correlation analysis.
- FIG. 10 is described with reference to the 1-D x-direction cross-correlation module 925 . It is understood that the 1-D y-direction cross-correlation module 920 functions equivalently for the y-direction.
- the process starts 1010 with a current reference image, RefX(x), in the system obtained from the original location of the optical pointing device 130 .
- the new image data signal that is received as a result of a movement of the optical pointing device 130 is transmitted along the second image data line 615 and read 1015 by the 1-D x-direction cross-correlation module 925 .
- the 1-D x-direction cross-correlation module 925 converts 1020 the image data signal into digital values.
- the converted data signal is stored 1025 in the memory of the 1-D x-direction cross-correlation module 925 as NewX(x), which is equivalent to the image data signal, but in a digital matrix form.
- the 1-D x-direction cross-correlation module 925 activates 1045 a signal strobe_x that is sent to the microcontroller 650 over the x-strobe line 652 .
- a current unidimensional x-direction set of image signals and a current unidimensional y-direction set of image signals, respectively, become a reference set of image signals for the x-direction and the y-direction, respectively.
- the transfer of the new set of image data signals into the memory of the 1-D cross-correlation module 925 , 920 holding the reference set of image data signals occurs after activation of the x-control 635 or the y-control 630 accordingly.
- the x-control 635 and y-control 630 function as described above with respect to FIGS. 6 and 7 .
- the reference set of images is left unchanged for this direction unless the cumulative displacement detected in the other direction corresponds to a sizable fraction, e.g., one-fourth, of the photosensor array. If there is a sizable fraction, a refresh of the reference image signal is performed using a new, current, image signal.
- the refresh process is similar to that described above in FIGS. 6 and 7 . This technique effectively reduces any loss of sensitivity for low-speed displacements either in the x-direction or the y-direction, while ensuring the reference image signal to be at least partly correlated with the new image signal. In addition, as discussed above, the “snapping” effect is also reduced to further increase displacement accuracy.
- the present invention beneficially provides for an optical pointing device that has few, if any, mechanical moving parts.
- the present invention is advantageously capable of operating on a surface capable of diffusely scattering a collimated beam 305 from a light source having a coherent light component so that a diffusely reflected image of the collimated beam 305 can be received by the optical sensing assembly 260 .
- the optical sensing assembly 260 provides optically matched optical elements 310 a , 310 b and photosensor arrays 320 a , 320 b that allow for speckle images that are generated by passing the diffusely scattered image of the illumination spot 390 through the optical elements 310 to be captured and utilized for determining displacement detection for an optical pointing device 130 .
- the present invention advantageously provides for 1-D as well as 2-D cross-correlation analysis to determine displacement thereby beneficially reducing computational workloads and reducing overall power consumption.
Abstract
An optical detection system and method detects movement of an optical pointing device in a data processing environment. The system works with any surface than can diffusely scatter a collimated beam from a coherent light source. Specifically, the system comprises a coherent light source and an optical sensing assembly. The optical sensing assembly comprises a plurality of photosensor arrays and a plurality of optical elements. Each photosensor array includes pixels of a particular size and shape. Each optical element has an artificially limited aperture and is associated, through optical matching, with a respective photosensor array. The coherent light source generates a collimated beam that is diffusely reflected off of the surface. The optical sensing assembly receives the diffusely reflected, or scattered, collimated beam and passes it through the artificially limited apertures of the optical elements to the associated corresponding photosensor array. Passing the scattered light through the optical elements generates speckle images that appear on the pixels of the photosensor arrays. Based on the pixel shape, a pixel value associated with the speckle image provides a speckle image data signal. When there is translation of the pointing device, a new set of speckle images, each reassembling to a translated version of the previous speckle image, are generated and another speckle image data signal is generated. The new and the previous speckle image data signals are then used in a motion detection analysis to determine the points of the two data signals that give a displacement value.
Description
- This application is a continuation of U.S. patent application Ser. No. 09/895,749, filed on Jun. 29, 2001, entitled “Optical Detection System, Device, and Method Utilizing Optical Matching,” which is a continuation of U.S. patent application Ser. No. 08/869,471, filed on Jun. 5, 1997, entitled “Optical Detection System, Device, and Method Utilizing Optical Matching” (now U.S. Pat. No. 6,256,016), both of which are incorporated by reference herein in their entirety.
- 1. Field of the Invention
- The present invention relates to pointing devices for cursors on video display screens in a data processing environment. More particularly, the present invention relates to an optical system, device, and method for imaging a surface to perceive a displacement of the surface without having mechanically moving parts or without requiring a specially patterned surface.
- 2. Description of the Related Art
- Pointing devices, such as a mouse or a trackball, are well known peripheral devices in data processing environments. Pointing devices allow for cursor manipulation on a visual display screen of a personal computer or workstation, for example. Cursor manipulation includes actions such as rapid relocation of a cursor from one area of the display screen to another area or selecting an object on a display screen.
- In a conventional electromechanical mouse environment, a user controls the cursor by moving the electromechanical mouse over a reference surface, such as a rubber mouse pad so that the cursor moves on the display screen in a direction and a distance that is proportional to the movement of the electromechanical mouse. Typically, the conventional electromechanical mouse consisted of a mechanical approach where a ball is primarily located within the mouse housing and a portion of the ball is exposed to come in contact with the reference surface so that the ball may be rotated internally within the housing.
- The ball of the conventional electromechanical mouse contacts a pair of shaft encoders. The rotation of the ball rotates the shaft encoders, which include an encoding wheel that has multiple slits. A light emitting diode (“LED”), or similar light source, is positioned on one side of the encoding wheel, while a phototransistor, or similar photosensor, is positioned opposite to the LED. When the ball rotates, the rotation of the encoding wheel results in a series of light pulses, from the LED shining through the slits, that are detected by the phototransistor. Thus, the rotation of the ball is converted to a digital representation which is then used to move the cursor on the display screen.
- The conventional electromechanical mouse is a relatively accurate device for cursor manipulation. The electromechanical mouse, however, has drawbacks associated with many other devices that have mechanical parts. Namely, over time the mechanical components wear out, become dirty, or simply break down so that the cursor can no longer be accurately manipulated, if at all.
- An optical mouse reduces, and in some instances eliminates, the number of mechanical parts. A conventional optical mouse uses a lens to generate an image of a geometric pattern located on an optical reference pad. The conventional optical mouse uses a light beam to illuminate an optical reference pad having a special printed mirror geometric pattern. The geometric pattern is typically a grid of lines or dots that are illuminated by the light source and then focused by a lens on a light detector in the conventional optical mouse.
- Typically, the grids are made up of orthogonal lines with vertical and horizontal lines that are printed in different colors and so that when the grid is illuminated, the grid reflects light at different frequencies. The colors absorb light at different frequencies so that optical detectors of the optical mouse can differentiate between horizontal and vertical movement of the conventional optical mouse. The photodetector picks up a series of light-dark impulses that consist of reflections from the printed mirror surface and the grid lines and converts the impulses into square waves. A second LED and photodetector, mounted orthogonally to the first, is used to detect motion in an orthogonal direction. The conventional optical mouse counts the number of impulses created by its motion and converts the result into motion information for the cursor.
- The conventional optical mouse provides the advantage of reducing or eliminating the number of mechanical parts. The conventional optical mouse, however, has several drawbacks. One problem with the conventional optical mouse is that it requires an optical pad as described above. To eliminate the optical pad, a coherent light source was used with the conventional optical mouse. The coherent light source illuminated the surface directly below the mouse on most surfaces, except mirror-like surfaces. The use of a coherent light source, however, produced more problems.
- The first problem the conventional coherent light optical mouse incurs is from the use of coherent light and speckles. Speckles are a phenomenon in which light from a coherent source is scattered by a patterned surface, such as the grid, to generate a random-intensity distribution of light that gives the surface a granular appearance. In the conventional coherent light optical mouse it is necessary to generate images of speckles to replace the optical pad. The imaging resolution is given by a photosensor pitch, e.g., the distance between two neighboring pixels or the periodicity, Λ, of the detector, a value that typically ranges from 10 micrometers to 500 micrometers. Elements in the image plane having a size smaller than this periodicity are not properly detected.
- A pattern is improperly detected by an imaging device when it is too small. The image is ambiguous if the pattern is smaller than the pixel size. A measure of speckle size, or more precisely speckle average diameter Δ, can be shown as Δ=(2/π) (λ/AP), where λ is the light wavelength and AP is a measure of an aperture of the optical system. The aperture of the optical system may be defined as AP=(wp/di), where wp is half the diameter of the aperture and di is the distance from the lens to the image plane.
- Conventional coherent light optical systems found in the conventional coherent light optical mouse devices exhibit AP values in the range of 0.2 to 0.8. The maximal speckle size is then approximately 10λ. For commercially available coherent light sources (λ=0.6 to 0.96 micrometers), imaging such a small pattern is currently not achievable at full resolution with current semiconductor technology. Thus, ambiguous and hard to interpret data is read from the sensor when a speckle is smaller than the imaging resolution. This, in turn, leads to erroneous displacement estimates that adversely affect system performance by producing an erroneous displacement sign value.
- Conventional optical systems that use a coherent light source produce an illumination spot that must be correctly aligned with a sensor to generate a speckled surface image. Mechanical positioning of the illumination spot is achieved with some tolerance, such that the illuminated spot image on the image plane must be wider than the sensor to make sure the sensor is fully covered by the image of the illumination spot. Having a wide spot results in a reflected spot having a reduced power intensity that the photosensor array must detect. Thus, attempts by conventional optical systems to solve position tolerance, i.e., misalignment, were accompanied by a loss of reflected light that can be captured by the photosensor array.
- Another problem with conventional optical pointing devices based on speckle image analysis is sensitivity of an estimation scheme to statistical fluctuations. Because speckles are generated through phase randomization of scattered coherent light, the speckle pattern has a defined size on average, but can exhibit local patterns not consistent with its average shape. Therefore, it is unavoidable for the system to be locally subjected to ambiguous or hard to interpret data, such as where a speckle count observed by the imaging system is small.
- An additional problem in conventional optical pointing devices is attaining a small displacement resolution without significantly increasing costs due to increased hardware complexities and increased computational loads. Various methods exist to estimate relative displacement from the analysis of two images of a moving target based on correlation techniques. Typically the correlation between the newly acquired image and the previous image is computed, and the estimated displacement between the two images is found at the spatial coordinates where a peak of the correlation function occurs. An exhaustive search of the peak value is possible after all values of the cross-correlation function are computed.
- New images are acquired on a regular basis, at an acquisition rate allowing at least one common part of the image to be included in two successive snapshots, even at high speed. The smallest resolvable displacement, or displacement resolution, is the image resolution, e.g., the photodetector array periodicity Λ, divided by the optical magnification, mag, where mag=(di/do), and di, do are defined as the image distance and the object distance, respectively, as referenced to the lens position.
- For even higher displacement resolutions, sub-pixel displacement can be obtained through interpolation by a factor I, however with an excessive increase of computations. Evaluations of the cross-correlation function of two images of size M×M requires roughly 4 (M4) Multiply-And-Accumulate (MACs), which translates into 4 (M4)/T_acq instructions-per-second (MIPs/1,000,000), where T_acq is the time period between two acquisitions. Typically, T_acq is between 50 microseconds and 1 millisecond. Such large computational load required costly and power hungry digital hardware which is difficult to integrate in a small hand held pointing device.
- One more problem with conventional optical pointing devices based on cross-correlation detection is that they are insensitive to displacement occurring when the pointing device speed is lower than the image resolution divided by (mag*T_acq), that is for a displacement smaller than a pixel. Any diagonal displacement at low speed may be registered along one direction and ignored along the other depending on the two displacement components compared to the detection limit. This effect translates into the cursor being “snapped” along the fastest moving direction.
- Therefore, there is a need for a system and method that (1) provides for detection of motion of an optical pointing device relative to a surface; (2) provides an optical detection system with an optical sensing assembly having an optical element with an artificially limited aperture that is matched with a photosensor array to generate a speckle image and an image data signal therefrom; (3) provides an optical detection system with an optical sensing assembly having one or more lenses optically matched with one or more photosensor arrays to generate a speckle image and an image data signal therefrom; and (4) provides a method for generating an unambiguous image data signal to determine displacement relative to a surface.
- Generally, the present invention includes an optical detection system, device, and method for detection of motion of an optical pointing device relative to a surface. The system and method of the present invention includes a coherent light source, an optical sensing assembly, a cross-correlation module, and a microcontroller.
- The coherent light source, for example, a laser diode, produces a coherent light beam that generates an illumination spot on a surface, or object plane, and is scattered off of the surface. The scattered light is directed towards, and received by, the optical sensing assembly. The optical sensing assembly includes one or more photosensor arrays and one or more optical elements. Each photosensor array of the plurality of photosensor arrays includes pixels of a particular size and a defined shape. The pixel is a single photosensitive element in the photosensor array. In addition, each optical element of the plurality of optical elements includes an artificially limited aperture. The received reflected illumination spot passes through the optical elements and forms speckle images on the photosensor, or image, plane.
- The optical sensing assembly is configured so that each artificially limited aperture is optically matched, either isotropically for a square pixel or anisotropically for other pixel shapes, to a corresponding photosensor array based on that photosensor array's pixel shape. Optical matching allows for the set of speckle images, having a varying speckle size, to have a single speckle cover at least one pixel of the photosensor array. Note that optical matching makes sure that the average size of a speckle image is larger than the pixel for both x and y directions. The pixel values from the speckle image that are received by the photosensor array provides an unambiguous speckle image data signal that is stored in a storage medium for further processing. If the pixel values of the speckle images are captured and converted to digital form for storage, the storage medium may be digital memory. If pixel values of the speckle images are captured and directly stored in voltage form, the storage medium may be an analog memory, such as a capacitor array, e.g., a bucket brigade device (“BBD”) or a charge coupled device (“CCD”).
- When there is movement of the optical mouse, the optical sensing assembly generates a new set of speckle images on the pixels of the photosensor arrays. For a displacement smaller than the illumination spot, the displacement of the surface translates into an equivalent speckle image displacement. The new unambiguous speckle image data signal generated by the photosensor arrays is captured in the storage medium. The new speckle image data signal and the previous speckle image data signal that are stored in the storage medium are then used to perform an image motion detection calculation, such as a cross-correlation analysis, using a cross-correlation module to determine the displacement of the two sets of speckle images. The calculated displacement corresponds to the movement of the optical pointing device.
- One cross-correlation analysis can occur when there is a multi-resolution image scheme. In particular, the cross-correlation analysis between the new speckle image data signal and the previous speckle image data signal is computed over a limited set of points. In particular, this set of points is all points in a low resolution image area plus a small range of points around the estimated displacement in a high resolution image area. The displacement related to the movement is determined by where a cross-correlation function of the cross-correlation analysis peaks. Using and applying the cross-correlation analysis over a limited set of points significantly reduces the processing power necessary to achieve a desired precision of determining displacement, or movement, of the optical pointing device.
- Another cross-correlation analysis can occur where there is a single resolution image scheme. In particular, the cross-correlation analysis between the new speckle image data signal and a reference, or previous, speckle image data signal is computed in one dimension—along a direction perpendicular to the elongated speckle images. The effects of lateral motion from the other direction is minimized because the speckles are elongated in that direction, therefore, producing little change in the image data signal as long as lateral displacement is smaller than the largest dimension of a pixel of a photosensor array. The one-dimensional cross-correlation analysis reduces power consumption because fewer calculations are required to determine displacement of the optical pointing device.
- Generally, a method of the claimed invention includes producing a coherent light beam and scattering the coherent light beam off of a surface. The scattered coherent light is received by an optical sensing assembly. The received scattered coherent light travels through a plurality of optical elements, where each optical element includes an artificially limited aperture that is matched with a photosensor array of a plurality of photosensor arrays. Through optical matching, the speckle image generated through each optical element is passed onto an associated photosensor array on which each speckle has a size larger than the pixel size on average.
- The optically matched photosensor arrays and corresponding artificially limited aperture of the optical elements generate a set of unambiguous speckle image signals that is stored in a storage medium. A cross-correlation analysis is performed between the unambiguous image signal that is stored and a subsequent unambiguous image data signal that is generated at periodic instances when movement is detected within the system. Precision of determining a displacement is attained through the search of a cross-correlation function over a limited set of points, where the displacement is found at the coordinates where the cross-correlation function of the cross-correlation analysis peaks.
- The claimed invention advantageously provides an optical detection system that detects movement of an optical pointing device relative to a surface that can generate speckle images. The claimed invention includes an optical sensing assembly having one or more optical elements and one or more artificially limited apertures that are optically matched to a plurality of photosensor arrays that generate an unambiguous image data signal from a speckle image formed from a diffusely scattered coherent light beam. The unambiguous image data signal is used to detect movements with greater precision without requiring greater system resources such as computational power and/or illumination power. Further, the claimed invention overcomes the adverse affects of position tolerance by allocating additional identical optical elements for each photosensor array so that the overlapping images of the illumination spot are generated to adequately cover each photosensor array even with worst case misalignment considerations.
- The features and advantages described in the specification are not all inclusive and, in particular, many additional features and advantages will be apparent to one of ordinary skill in the art in view of the drawings, specification, and claims. Moreover, it should be noted that the language used in the specification has been principally selected for readability and instructional purposes, and may not have been selected to delineate or circumscribe the inventive subject matter.
-
FIG. 1 is a diagram of an operating environment in accordance with the present invention. -
FIG. 2 a is an external diagram of an optical pointing device in accordance with the present invention. -
FIG. 2 b is a partial internal diagram of an optical pointing device in accordance with the present invention. -
FIG. 3 is a diagram illustrating generally an optical sensing assembly in accordance with the present invention. -
FIG. 4 a is a diagram illustrating a cross-sectional view of the optical sensing assembly in accordance with the present invention. -
FIG. 4 b is a symbolic view illustrating a speckle field image on a photosensor array in accordance with the present invention. -
FIGS. 4 c and 4 d are symbolic views illustrating an ambiguous speckle image verses an unambiguous speckle image. -
FIG. 5 a is a diagram of an optical sensing assembly having multiple optical elements for each photosensor array in accordance with the present invention. -
FIG. 5 b is a symbolic view illustrating multi-resolution capabilities of the optical sensing assembly in accordance with the present invention. -
FIG. 6 is a block diagram illustrating a multi-resolution displacement detection system in accordance with the present invention. -
FIG. 7 a is a flow diagram illustrating operation of the multi-resolution displacement detection system in accordance with the present invention. -
FIG. 7 b is a flow diagram illustrating operation of a 2-D cross-correlation module and microcontroller of the multi-resolution displacement detection system in accordance with the present invention. -
FIG. 8 is a symbolic view illustrating the artificially limited and anisotropic aperture in accordance with the present invention. -
FIG. 9 is a block diagram illustrating an anisotropic motion detection system in accordance with the present invention. -
FIG. 10 is a flow diagram illustrating operation of a 1-D cross-correlation module in accordance with the present invention. -
FIG. 1 is a diagram of an embodiment of an operatingenvironment 100 in accordance with the present invention. The operatingenvironment 100 includes anoptical pointing device 110, asurface 120, and acomputer system 130. Thesurface 120 may be any surface that can diffusely reflect light, such as a table or desk, for example. Thecomputer system 130 may be a conventional computer system such as an IBM PC™, Apple MacIntosh™, Sun SPARCStation™, or the like. Thecomputer system 130 includes a processor, a memory, a display screen, and an input port for a pointing device. Theoptical pointing device 110 is coupled to the input port of thecomputer system 130. It is noted that although theoptical pointing device 110 may be coupled to the input port of thecomputer system 130 using a wire connection such as an opticalpointing device cable 140, other coupling connections such as infrared or radio frequency control may also be applicable. -
FIG. 2 a is an external diagram of theoptical pointing device 130 in accordance with the present invention. Externally, theoptical pointing device 130 includes ashell housing 210 having anunderside 220. Theunderside 220 includes a coherentlight emission area 230 for emission of a coherentlight source 250 and alight detection area 240 for anoptical sensing assembly 260. In a preferred embodiment of the present invention, the coherentlight source 250 is a laser diode. In an alternative embodiment, the coherentlight source 250 may also be another coherent light emitting source or may be a partially coherent light emitting source, in which the coherent light component is used by theoptical pointing device 130. The laser diode comprises a light emitting die and a transparent package that performs collimation or beam shaping. In an alternative embodiment, the laser diode comprises a light emitting die and an independent beam shaping optical element to perform collimation or other beam shaping. Also, in accordance with the present invention, theunderside 220 of theoptical detection system 110 is placed on or in close proximity to thesurface 120 during operation. -
FIG. 2 b is a partial internal diagram of theoptical pointing device 130 in accordance with the present invention. Internally, theoptical pointing device 130 includes the coherentlight source 250 and theoptical sensing assembly 260. In one embodiment, the coherentlight source 250 is directed such that a coherent light beam would be emitted through the coherentlight emission area 230 towards thesurface 120. The coherent light beam from the coherentlight source 250 is then partially reflected off of thesurface 120 toward thelight detection area 240, and more specifically, theoptical sensing assembly 260. In a preferred embodiment, the coherent light beam is acollimated beam 305. In an alternative embodiment, a quasi-collimated beam is used, where a certain degree of convergence or divergence is applied. Further, in a preferred embodiment, the coherentlight emission area 230 and thelight detection area 240 are collectively a single area. -
FIG. 3 is a diagram illustrating theoptical sensing assembly 260 in accordance with the present invention. Theoptical sensing assembly 260 comprises one or more optical elements 310, one or more photosensor arrays 320, a transparent printedcircuit board 340, and moldedfittings 350. For purposes of illustration, theoptical sensing assembly 260 is described with twooptical elements photosensor arrays photosensor array - The transparent printed
circuit board 340 includes afirst side 345 a and asecond side 345 b. Thefirst side 345 a includes amicrolens array 360, which is further discussed below. Alternatively, an opaque printed circuit board may be used, however, it must be fitted with openings to allow light to pass through to thephotosensor arrays second side 345 b, which is opposite thefirst side 345 a, includes thephotosensor arrays microlens array 360. - Each
optical element lens limited aperture fittings 350. In the preferred embodiment, the focal length, f, is between 1 mm and 5 mm, for example. In the preferred embodiment, each artificiallylimited aperture respective lens lens fittings 350 are coupled to thelens fittings 350 may be integrated with eachlens optical elements refractive microlens array 360. Alternatively, theoptical elements diffractive microlens array 360, in which case the aperture function is directly combined with the lens function. Themicrolens array 360 includes integrated aperture openings for eachoptical element microlens array 360 may include the beam shaping optical element. - Each
optical element microlens array 360 so that each artificially limited aperture is centered about its respective aperture opening. The assembledmicrolens array 360 is coupled to thefirst side 345 a of the transparent printedcircuit board 340 of theoptical sensing assembly 260. In a preferred embodiment, object distance, do, and image distance, di, are related by (1/f)=(1/do)+(1/di), where f is the focal length and mag=(di/do), where mag is the magnification of the optical imaging system. - Each
photosensor array more pixels 420, further illustrated as individual squares inFIG. 4 b. Apixel 420 is a single photosensitive element in thephotosensor array pixels 420 can range from 4 by 4 to 30 by 30, for example. In one embodiment, eachpixel 420 has a defined isotropic size and shape where the size may be defined as the distance between two neighboringpixels 420 as opposed to the size of the light sensitive area of the pixel. Thephotosensor arrays pixels 420. The distance between twosuccessive pixels 420 is a photosensor pitch, e.g., the periodicity, Λ. The photosensor pitch defines the size of a pixel and describes the resolution of the system, e.g., the smallest discernible element in the image plane. - The
microlens array 360 and thephotosensor arrays photosensor array illuminated spot 390 obtained through a spot fan-out. Spot fan-out is when the image of the sameilluminated spot 390 is received at different photosensor arrays within theoptical sensing assembly 260 after passing through the associated optical element 310. In a preferred embodiment, spot fan-out results when thecenter 390 a′ of thespot 390, thecenter 390 b′ of alens aperture center 390 d′ of aphotosensor array - Using a spot-fan out feature, the collimated
beam 305 from the coherentlight source 250 can be of a minimal size, about the size of the largest photosensor array. The minimal size of the collimatedbeam 305 produces ahigh intensity spot 390 that is easier to detect reliably, while reducing power consumption within the system through the use of a low illumination coherentlight source 250. This is in contrast to conventional systems where the collimated beam must be wide enough so that the image of an illumination spot covers a surface large enough to include all the photosensor arrays, thus requiring a coherent light source that consumes greater power. In accordance with the present invention, the spot fan-out feature may also be used to generate multiple images by scattering, or diffusely reflecting, the sameilluminated spot 390 through the optical elements 310 on one or morephotosensor arrays photosensor array -
FIG. 4 a is a diagram illustrating a cross-sectional view of the optical sensing assembly in an optical detection system in accordance with the present invention. In particular, theoptical sensing assembly 260 is shown to include themicrolens array 360 having theoptical elements lenses limited apertures photosensor arrays circuit board 340. Theoptical sensing assembly 260 is also shown to include an air or atransparent adhesive 342 layer between themicrolens array 360 and the transparent printedcircuit board 340. - In one embodiment, the
photosensor arrays circuit board 340 using, for example, a flip-chip mounting technology. Further, in a preferred embodiment, themicrolens array 360 is a diffractive microlens array. A diffractive microlens array allows for an artificially limited aperture to be included by design in the diffractive pattern together with the lens function so that the aperture is aligned with the lens. - As illustrated in
FIG. 3 and again inFIG. 4 a, the collimatedbeam 305 from a coherentlight source 250 is directed towards asurface 120. The collimatedbeam 305 produces theillumination spot 390, including aspot center 390 a′, on thesurface 120. Thesurface 120 scatters, i.e., diffusely reflects, the collimatedbeam 305 at the location of thespot 390 a towards the lenses 315 of theoptical sensing assembly 260. Thescattered light 305′ passes through the central point, f′, of thelenses limited apertures photosensor arrays scattered light 305′ that passes through theoptical elements photosensor arrays -
FIG. 4 b illustrates an example of a speckle field image that appears on thephotosensor arrays more speckles 410. Eachphotosensor array pixels 420 that are isotropic, i.e., of the same size in both the x-direction and the y-direction (e.g., a square) relative to an x-y plane, with respect to other pixels of the other photosensor array. Eachphotosensor array optical element FIG. 3 , as well as theillumination spot 390 location, so that the spot fan-out feature is applicable. - A symbolic view of the artificially
limited aperture FIG. 4 b as a firstdotted outline 330 a′, 330 b′ on eachphotosensor array dotted outline 390″ illustrates the size of the image of theillumination spot 390 relative to thephotosensor array speckle images 410 that appear on thephotosensor arrays - In the symbolic view of
FIG. 4 b, the speckle field image that is received by thephotosensor arrays illumination spot 390 is received and passed through theoptical element limited aperture respective photosensor array scattered light 305′ from the reflectedillumination spot 390 and is received and passed through theoptical sensing assembly 260. The scattered light from theillumination spot 390 that is passed through theoptical elements photosensor arrays - The speckle field image is unique to each
photosensor array beam 305 that is diffusely reflected from theillumination spot 390 a′ off of thesurface 120, through theoptical elements photosensor arrays photosensor arrays speckle image 410. -
FIGS. 4 c and 4 d provide an example illustrating an ambiguous speckle image versus and unambiguous speckle image. Generally, an unambiguous speckle image data signal is obtained when it is known that the signal delivered by thepixels 420 capturing thespeckle 410 will see at least some of the output value differ if a small displacement is applied to the surface of thespeckle 410. - For example, in
FIG. 4 c, thespeckle 410 is shown moving from point A to point B on a photosensor array 320 of an optical pointing device. The speckle displacement is a result of movement of an optical pointing device. The output of apixel 420 of the photosensor array 320 is the sum of the light that impinges on thepixel 420 and because this sum is identical for both positions of thespeckle 410, despite the new location of thespeckle 410, there is only one set of values for calculating displacement. By contrast, inFIG. 4 d, thespeckle 410 is shown moving from point C to point D. In accordance with the present invention, the speckle translation is a result of translation of theoptical pointing device 130. Here, there is a change in pixel value as thespeckle 410 moves from onepixel 420 c into asecond pixel 420 d so that onepixel 420 c sees its output get lower while theother pixel 420 d sees its output get larger. The result is two sets of values for calculating displacement of theoptical pointing device 130. Thus, thespeckle 410 inFIG. 4 d produces an image signal that is unambiguous. - The unambiguous speckle image data signal allows for reconstruction of the
speckle image 410 from thepixels 420 as further described below. The unambiguous data signal provides unambiguous and reliable motion detection when applying a motion detection analysis, such as a cross-correlation analysis, to the speckle image data signal. Specifically, thespeckle images 410 are captured as speckle image data by thephotosensor arrays optical pointing device 110 as will be further described below. - The unambiguous speckle image data signals obtained from the
speckle image 410 illustrated inFIG. 4 b are obtained through optical matching. Optical matching describes a property of an optoelectronic system, such as in an optical sensing assembly, matching a relevant feature of the optical subsystem to a relevant feature of the electronic photosensor array subsystem. In one embodiment, optical matching is a result of artificially limiting the optical aperture 330 for a given illumination wavelength so as to match the periodicity, or pitch, A, of the photosensor array 320. The optical matching relationship becomes AP<(2/π)(λ/Λ), where AP is the aperture, λ is the light wavelength, and Λ is the periodicity, or pitch, of the photosensor array 320. For an anisotropic photosensor array, i.e., a photosensor array 320 having a different length and width, the optical matching relationship with reference to an x-y plane becomes APx<(2/π)(λ/Λx) for an x-direction and APy<(2/π)(λ/Λy) for a y-direction. Thus, for a photosensor array 320 that is onepixel 420 in the x-direction andM pixels 420 in the y-direction, e.g., a (1×M) photosensor array 320, the pitch, Λ, is thepixel 420 length in the x-direction and the interpixel spacing for the y-direction. Similarly, for a photosensor array 320 that isM pixels 420 in the x-direction and onepixel 420 in the y-direction, e.g., a (M×1) photosensor array 320, the pitch is the pixel length in the y-direction and the interpixel spacing for the x-direction. - As a result of optical matching, the average diameter of a speckle in the
speckle image 410 is larger than thepixel 420 size, where size refers to the pitch, Λ. For anisotropic pixels, further discussed below, optical matching is achieved when the average speckle diameter along the x-direction and the y-direction, respectively, are larger than the size of thepixel 420, along both the x-direction and the y-direction, respectively. Optical matching suppresses the occurrences of an ambiguous sample set of speckle image data signals generated byspeckles 410 that are smaller than thepixel 420 size. This is because by matching the aperture 330 to the pitch, Λ, through the optical matching relationship, speckles 410 are larger than asingle pixel 420 on average which makes motion detection from successive sets of speckle image data signals reliable. When optical matching is not achieved, difficulty arises fromspeckles 410 that are smaller than thepixel 420 size that produce image data signals that may not vary when a small displacement is applied to them. - In a preferred embodiment, optical matching is obtained through artificially limiting the aperture, AP, 330 a, 330 b of each
optical element speckle image 410. The unambiguous image data signal is referred to as a fully resolved data signal and allows for a reliable cross-correlation analysis for determining displacement. A fully resolved data signal describes a data signal that allows a faithful reproduction of the image covering the photosensor array 320 when the speckle image data signal was generated. A fully resolved data signal precludesspeckles 410 smaller than apixel 420 size since it is not known from the signal if one or more speckles were covering thepixel 420. Successive speckle images obtained from an optically matched optical sensing assembly allow for a cross-correlation analysis that provides a displacement value by looking for the peak of the cross-correlation function. - In a preferred embodiment of the present invention, the artificially
limited apertures optical element photosensor array speckle image 410 includes a speckle average size covering at least onepixel 420 of thephotosensor array optical elements apertures photosensor arrays - As shown in
FIG. 5 a, theoptical assembly 260 in accordance with the present invention may use multiple optical elements 310 a-1-310 a-n, for example five optical elements 310 a-1-310 a-5, each having an artificially limited aperture 330, for each photosensor array 320. This configuration alleviates the affects of position tolerance, or misalignment. In particular, the multiple optical elements 310 a-1 to 310 a-5 provide overlapping images derived from the scatteredillumination spot 390 passing through each so that the matchedphotosensor array 320 a is adequately covered with light. Thus, thepixels 420 of thephotosensor array 320 a can detect the image of theillumination spot 390 even with a worst case misalignment of the optical elements 310 and thephotosensor arrays 320 a because thephotosensor array 320 a is entirely exposed by a speckle image field generated through any of the multiple optical elements 310 a-1 to 310 a-5. - To lower computational load, and thus lower power consumption, for determining displacement of the
optical pointing device 110, a multi-resolution system is used in accordance with the present invention.FIG. 5 a diagramatically illustrates theoptical assembly 260 configuration that can be used in either a single resolution or multi-resolution environment. For a multi-resolution environment, there will be at least two sets of optical elements 310 configured as described above. -
FIG. 5 b illustrates a multi-resolution environment through a symbolic view ofspeckle images 410 in accordance with the present invention. To achieve multi-resolution capabilities, theoptical sensing assembly 260 includes a multi-element setup. In the multi-element setup, differentoptical elements photosensor arrays speckle images 410. - The different artificially
limited apertures speckle images 410 of different sizes. For example, a large aperture creates a smaller speckle image as illustrated with thesecond photosensor 320 b. By contrast, a small aperture creates a larger speckle image as illustrated with thefirst photosensor 320 a. Thephotosensor arrays speckle images 410. To achieve unambiguous data signals to detect movement, each of theoptical elements photosensor arrays optical sensing assembly 260. - In a preferred embodiment each
optical element photosensor array limited aperture pixel 420. For example, anoptical element 310 a having alarge aperture 330 a is matched with aphotosensor array 320 a having smaller pixels and thus, a smaller pitch, Λ, as shown inFIG. 5 b, to produce a high resolution speckle image data signal. By contrast, anoptical element 310 b having asmall aperture 330 b is matched with aphotosensor array 320 b having larger pixels and thus, larger pitch, Λ, between pixels, as shown inFIG. 5 b, to produce a low resolution speckle image data signal. The resulting plurality ofspeckle images 410 of different sizes and resolution among differentphotosensor arrays illumination spot 390 after passing through the optical elements 310 as described above. As will be described below, the multi-resolution architecture requires less power consumption as computational loads are significantly decreased. -
FIG. 6 is a block diagram illustrating the multi-resolutiondisplacement detection system 605, including theoptical sensing assembly 260, in accordance with the present invention. Themulti-resolution detection system 605 obtains the multi-resolution architecture of speckle images as discussed above and determines a two-dimensional displacement of theoptical pointing device 110 as further described below. - The
multi-resolution detection system 605 includes the coherentlight source 250, theoptical sensing assembly 260, a first low-resolution data signalline 610, a second high-resolution image data signalline 615, a two-dimensional (“2-D”) y-direction cross-correlation module 620, a two-dimensional (“2-D”)x-direction cross-correlation module 625, a y-control line 630, ax-control line 635, a y-change line 640, ax-change line 645, a y-acknowledge line 637, ax-acknowledge line 647, a y-strobe line 642, ax-strobe line 652, amicrocontroller 650, a first and a secondmicrocontroller output line line interface module 660, a first lineinterface output line 665 a, and a second lineinterface output line 665 b. - The y-
change line 640 and thex-change line 645 are in one embodiment 8-bit bus lines so that the signals along those lines, Δy signal and Δx signal, respectively, can be any integer between −127 and +127. The 2-D y-direction and the 2-Dx-direction cross-correlation modules x-direction cross-correlation modules - A
first photosensor 320 a and asecond photosensor 320 b of theoptical sensing assembly 260 are coupled to both the 2-D y-direction cross-correlation module 620 and the 2-Dx-direction cross-correlation module 625 through the first and the second image data signalline direction cross-correlation module 620 is coupled to themicrocontroller 650 through the y-control line 630, the y-change line 640, the y-acknowledge line 637, and the y-strobe line 642. The 2-Dx-direction cross-correlation module 625 is coupled to themicrocontroller 650 through thex-control line 635, thex-change line 645, thex-acknowledge line 647, and thex-strobe line 652. Themicrocontroller 650 is coupled to the coherentlight source 250, such as a laser diode. Themicrocontroller 650 is also coupled to theline interface 660 through the first and the secondmicrocontroller output lines line interface 660 is a standard communication protocol, such as a serial port communication protocol or a universal serial bus protocol, for example. It is noted that the photosensor arrays 320,microcontroller 650, andcross-correlation modules -
FIG. 7 a illustrates the operation of the multi-resolutiondisplacement detection system 605 in accordance with the preferred embodiment of the present invention. The process starts 705 when the collimatedbeam 305 is produced 710 from the coherentlight source 250 of theoptical pointing device 130. The collimatedbeam 305 is scattered 715 off of thesurface 120. The scattered light, is received 720 by theoptical sensing assembly 260 so that it is fanned-out 725 through thelenses limited apertures optical elements appropriate photosensor array optical elements limited apertures photosensor array limited apertures photosensor arrays pixel 420 of the associatedphotosensor array - Using optical matching with the pixel values from the image speckle, an unambiguous image data signal is generated 730. The image data signal is the collection of all pixel values that are generated by the
photosensor array photosensor arrays - The newly received, or current, unambiguous image data signal is stored 735 in the memory, or storage medium, of the
cross-correlation modules direction cross-correlation module 620 and the 2-Dx-direction cross-correlation module 625 perform a cross-correlation analysis with unambiguous image data signals for the y-direction and the x-direction, respectively. - The 2-D x-direction and 2-D y-
direction cross-correlation modules cross-correlation module - Cross-correlation is a measure of the similarity between a reference image and an unknown image. For example, a large cross-correlation may mean there is a high degree of similarity between the reference image and the unknown image. A cross-correlation function provides the same measure of similarity, but computed for the reference image and the unknown image to which a displacement, a shift of (m, n), has been applied. The shift (m, n) provides an argument for the cross-correlation function.
- If the cross correlation function is maximal for m=mo and n=no, it means that the displaced, or shifted, image most similar to the reference image is the unknown image to which a displacement (mo, no) has been applied. Equivalently, if a pattern is recorded at two instants, and an unknown movement occurred between the two instants, the displacement can be deduced by finding the argument of the cross-correlation function where the peak is found. For example, assuming that the current image data signal is f(x, y) and the reference image data signal is g(x, y), the cross-correlation function R(m, n) calculated for a displacement, (m, n), is R(m, n)=ΣxΣyf(x, y)g(x-m, y-n). The estimated displacement, Δx and Δy, is then found by determining where the peak of R(m, n) occurs in the search range such that R(Δx, Δy)=Max (R(m, n)) with (m, n)εsearch range.
- The peaks of the cross-correlation function provide the points, Δx and Δy, respectively, that determine the two-dimensional displacement of a speckle image that occurred since the last refresh, e.g., when the current reference set of image data signals was transferred from the current image in the memory of the 2-D y-direction and 2-D
x-direction cross-correlation modules cross correlation module 625 and the y-directioncross correlation module 620, respectively, to themicrocontroller 650 through the y-change andx-change lines - The 2-D x-direction and 2-D y-
direction cross-correlation modules photosensor array direction cross-correlation modules - In one embodiment, multi-resolution displacement detection includes the 2-D x-direction and 2-D y-
direction cross-correlation modules optical sensing assembly 260 is common for both directions.FIG. 7 b (1-3) is a flow diagram illustrating operation of the 2-D cross-correlation modules microcontroller 650 in accordance with the present invention. For purposes of simplicity, the flow diagram will be discussed with respect to the 2-Dx-direction cross-correlation module 625 and it is understood that similar principles apply for the 2-D y-direction cross-correlation module 620. Each instance when a new speckle image is acquired, a new set of image data signals for low-resolution, NewL(x, y), and for high-resolution, NewH(x, y), is acquired and stored into a memory. Thus, the memory stores two reference sets of image data signals, one for the x-direction and one for the y-direction, both of which are obtained from the previously acquired set of image data signals for low resolution, RefL1(x, y), and for high-resolution, RefH1(x, y). - The 2-D x-direction and 2-D y-
direction cross-correlation modules start 770 of operation, low resolution data signals (from afirst photosensor array 320 a, for example) and high resolution data signals (from asecond photosensor array 320 b, for example) are read 772 from thephotosensor arrays photosensor arrays - For a displacement, (m, n), a low resolution cross-correlation analysis (RL(x, y)) is computed 778, where (m, n)ε[1 . . . Mx, 1 . . . My] and Mx and My are the number of pixels on the low resolution photosensor 320 a along the x-direction and the y-direction. Thus, the cross-correlation function is RL(m, n)=ΣxΣyNewL(x, y)RefL(x-m, y-n), where RefL is a current low-resolution reference image. Once the cross-correlation function is performed, peak values (m0, n0) are identified 780 such that RL(m0, n0)=Max(RL(m, n)).
- Once the peak values, mo and no, are identified 780, the search range [((LHR)*(m0))−LHR . . . ((LHR)*(m0))+LHR, ((LHR)*(n0))−LHR . . . ((LHR)*((n0))+LHR] is defined 782, where LHR is the resolution ratio=(ΛH (high resolution array))/(ΛL (low resolution array)). For the displacement (m, n) a high resolution cross correlation analysis (RH(x, y)) is computed 784 for (m, n)εsearch range, so that RH(m, n)=ΣxΣy NewH(x, y)RefH(x-m, y-n), where RefH is a high resolution current reference image. Once the cross-correlation function is performed, a peak value (m1, n1) is identified 786 in the search range so that RH(m1, n1)=Max(RH(m, n).). A value for m1 is forwarded 788 to the
microcontroller 650 as a value Δx through thex-change line 645 and the signal strobe_x is activated 790 by the x-directioncross correlation module 625. - The system determines 792 whether the
microcontroller 650 activated an acknowledge_x signal. The acknowledge_x signal is sent to the 2-D x-directioncross correlation module 625. A control_x signal is read 794 by the 2-D x-directioncross correlation module 625 and, if activated 796, the reference image is refreshed 798 so that RefL1(x, y)=NewL(x, y) and RefH1(x, y)=NewH(x, y). Once the reference image is refreshed 798, the strobe_x signal is deactivated 800. If control_x is not activated, the system directly deactivates 800 the strobe_x signal. - The refresh includes transferring the current image data signal set into the reference image data signal set upon activation of the x-control 635 or y-
control 630 by themicrocontroller 650 using a technique as further described below. This technique is shown to effectively reduce any loss of sensitivity for low speed displacements either in the x-direction or the y-direction of an x-y plane while ensuring that the reference set of image signals is at least partly correlated with the new image set. Thus, the present invention beneficially eliminates a “snapping” effect and provides greater precision for determining displacement. - If a non-zero displacement is transmitted to the
microcontroller 650 in the x-direction, and similarly in the y-direction, the new set of image signals becomes the reference set of image signals for the x-direction, and similarly for the y-direction, for use with the next set of image signal. The transfer of the new set of image data signals into the reference set of image memory in the x-direction and y-directioncross correlation modules microcontroller 650. If a zero displacement is transmitted to themicrocontroller 650 for any direction, the reference set of image signals is left unchanged, e.g., the x_control or y_control signals are not activated, for the particular direction unless the cumulative displacement, x_total and y_total, respectively, detected in the remaining direction corresponds to a sizable fraction, for example one-fourth, of the photosensor array. In such instances a refresh of the reference set of image data signals is performed using the current new set of image data signals. - Briefly, referring to the x-control 635 and the y-
control 630 lines, thex-control line 635 will be described with the understanding that the similar principles apply for the y-control line 630. Themicrocontroller 650 activates the x_control signal along thex-control line 635 when themicrocontroller 650 detects non-zero displacement along an x-direction, or when the cumulative displacement, y_total, since the last x-direction refresh along the y-direction is above a predetermined value, y_limit, such as an effective displacement equivalent to about one-fourth of the physical dimension of the photosensor array 320. This ensures that although there was no displacement along the x-direction since the last refresh, the displacement that occurred along y is not so big as to have moved allspeckles 410 present on the reference set of images outside the field of view of the photosensor array 320. Activation of the x_control signal along thex-control line 635 means that the new set of image data signals become the reference set of image data signals for the next set of image data signals. Specifically, the 2-Dx-direction cross-correlation module 625 transfers the content of the memory, or portion thereof, that stores the new set of image data signals to the memory, or portion thereof, that stores the reference set of image data signals. - In addition, the
microcontroller 650 acquires the displacement, Δx, as calculated by the 2-Dx-direction cross-correlation module 625. The acquired value of the displacement, Δx, is the computed displacement since the last refresh, i.e., the change in the reference image data signal. Themicrocontroller 650 then keeps a cumulative displacement, x_total, that is equal to the current x_total value plus the displacement, Δx. Periodically, for example, every 20 milliseconds, themicrocontroller 650 transmits x_total to thecomputer system 130 through theline interface 660 using a communication protocol such as a serial port communication protocol, universal serial bus communication protocol, or an IBM PS2™ mouse port communication protocol, for example. Once the x_total is transmitted to thecomputer system 130, x_total is reset to zero to begin accumulating a new displacement value as is further illustrated inFIG. 7 c. - It is noted that if desired, the cross-correlation analysis can be iteratively applied to even higher resolution until a desired precision of displacement is reached. The number of operations, that is, the number of cross-correlation function evaluations, needed to reach a desired precision is reduced significantly by searching the cross-correlation function only over a limited number of points by following the iterative search path.
- To achieve even greater computational power consumption savings, the optical elements may include artificially limited anisotropic apertures that are optically matched with associated photosensor arrays having a pitch, or periodicity, Λ, that is different for the x-direction and the y-direction so that a one-dimensional cross-correlation analysis may be performed.
FIG. 8 is a symbolic view illustrating speckles captured on photosensor arrays 320 having a pitch that is different in the x-direction versus the y-direction and which are optically matched with an associated optical element having the artificially limited anisotropic aperture in accordance with the present invention. - Artificially limiting the aperture anisotropically generates elongated speckles in the direction of the largest periodicity, Λ, where periodicity, or pitch, is the distance between two neighboring pixels, as described above. For example, looking at the symbolic view in
FIG. 8 , when the largest periodicity is in the x-direction, as with thefirst photosensor array 320 a, x-direction elongated speckles are generated so that the system is sensitive to movement in the y-direction. Similarly, when the largest periodicity is in the y-direction, as with thesecond photosensor array 320 b, y-direction elongated speckles are generated so that the system is sensitive to movement in the x-direction. In a preferred embodiment, each photosensor array 320 is comprised of M adjacentrectangular pixels 420 having a rectangular pixel shape of aspect ratio, N, where N is the ratio of the pixel length over the pixel width. When M equals N, the configuration produces square photosensor arrays 320. -
FIG. 9 is a block diagram illustrating an anisotropicdisplacement detection system 905 in accordance with the present invention. Similar to the multi-resolutiondisplacement detection system 605 inFIG. 6 , the anisotropic opticaldisplacement detection system 905 includes the coherentlight source 250, theoptical sensing assembly 260, a first image data signalline 610, a second image data signalline 615, a 1-dimensional (“1-D”) y-direction cross-correlation module 920, a 1-dimensional (“1-D”)x-direction cross-correlation module 925, the y-control line 630, thex-control line 635, the y-change line 640, thex-change line 645, the y-acknowledge line 637, thex-acknowledge line 647, the y-strobe line 642, thex-strobe line 652, themicrocontroller 650, the first and the secondmicrocontroller output line line interface module 660, and the first and the second lineinterface output line x-direction cross-correlation modules - A
first photosensor 320 a and asecond photosensor 320 b of theoptical sensing assembly 260 are respectively coupled to the 1-D y-direction cross-correlation module 920 and the 1-Dx-direction cross-correlation module 925 respectively through the first and the second image data signalline direction cross-correlation module 920 is coupled to themicrocontroller 650 through the y-control line 630, the y-change line 640, the y-acknowledge line 637, and the y-strobe line 642. The 1-Dx-direction cross-correlation module 925 is coupled to themicrocontroller 650 through thex-control line 635, thex-change line 645, thex-acknowledge line 647, and thex-strobe line 652. Themicrocontroller 650 is coupled to the coherentlight source 250, such as a laser diode. Themicrocontroller 650 is also coupled to theline interface 660 through the first and the secondmicrocontroller output lines - Similar to the multi-resolution
displacement detection system 605, theoptical pointing device 130 of the present invention having an anisotropic displacement detection system produces a collimatedbeam 305 from the coherentlight source 250. The collimatedbeam 305 is diffusely reflected, i.e., scattered, off of thesurface 120. The scattered light is received by theoptical sensing assembly 260 so that it is fanned-out through thelenses anisotropic apertures optical elements photosensor arrays - The optical elements 310 having the artificially limited
anisotropic apertures photosensor array anisotropic apertures photosensor arrays - Using optical matching with the pixel values from the image speckle, an unambiguous image data signal is generated because a single elongated speckle will cover on average a single elongated pixel. To obtain the image data signal for the 1-D cross-correlation analysis, the light intensity of a speckle image captured on a
photosensor array pixel 420 and is based on a conventional charge coupled device, a photogate system, or a photodiode. The image data signal that is produced is an unambiguous image data signal that is a sequential readout of all the pixel values, for example. It is noted that although a pixel clock is not shown, it is present for pixel value synchronization to indicate when the image data signal should be acquired as pixel values are sequentially output from thephotosensor arrays - The unambiguous image data signal is stored in the memory, or storage medium,
cross-correlation module direction cross-correlation module 920 and the 1-Dx-direction cross-correlation module 925 perform a cross-correlation analysis with unambiguous image data signals for the y-direction and the x-direction, respectively. - The anisotropic configuration performs a cross-correlation analysis in one dimension—along the direction perpendicular to the elongated speckle images. The effects of lateral motion from the other direction is minimized because the speckles are elongated in that direction, thus, producing little change in the image data signal as long as lateral displacement is smaller than about one-fourth of the largest dimension of a
pixel 420. The use of a one dimensional cross-correlation analysis produces significant power savings because computations to determine a displacement occur in only one dimension and therefore, further reduce the number of operations required to determine the displacement of theoptical pointing device 130. -
FIG. 10 is a flow diagram illustrating a 1-D cross-correlation analysis.FIG. 10 is described with reference to the 1-Dx-direction cross-correlation module 925. It is understood that the 1-D y-direction cross-correlation module 920 functions equivalently for the y-direction. The process starts 1010 with a current reference image, RefX(x), in the system obtained from the original location of theoptical pointing device 130. The new image data signal that is received as a result of a movement of theoptical pointing device 130 is transmitted along the secondimage data line 615 and read 1015 by the 1-Dx-direction cross-correlation module 925. The 1-Dx-direction cross-correlation module 925converts 1020 the image data signal into digital values. The converted data signal is stored 1025 in the memory of the 1-Dx-direction cross-correlation module 925 as NewX(x), which is equivalent to the image data signal, but in a digital matrix form. - For all xε[1 . . . Mx], where Mx is the number of pixels on the
photosensor 320 b, the process computes 1030 Rx(m) such that Rx(m)=Σx(NewX(x))(RefX(x-m)). The process then identifies 1035 the peak value mo such that Rx(mo)=Max(Rx(m)). After the peak value has been identified 1035, the process forwards the value mo to themicrocontroller 650 at the value Δx along thex-change line 645. The 1-Dx-direction cross-correlation module 925 activates 1045 a signal strobe_x that is sent to themicrocontroller 650 over thex-strobe line 652. Themicrocontroller 650 acknowledges the receipt of the value Δx and activates a signal of acknowledge_x. If the acknowledge_x signal is activated 1055 the control_x signal is read 1060 by the 1-Dx-direction cross-correlation module 925. If the 1-D x-direction cross-correlation module determines 1065 that the control_x signal is active, it refreshes 1070 the reference signal, RefX(x), such that RefX(x)=NewX(x). After therefresh 1070 is completed, the strobe_x signal is deactivated. - If there is a non-zero displacement in the x-direction or the y-direction, a current unidimensional x-direction set of image signals and a current unidimensional y-direction set of image signals, respectively, become a reference set of image signals for the x-direction and the y-direction, respectively. The transfer of the new set of image data signals into the memory of the 1-
D cross-correlation module control 630 accordingly. The x-control 635 and y-control 630 function as described above with respect toFIGS. 6 and 7 . - If there is a zero displacement for any direction, the reference set of images is left unchanged for this direction unless the cumulative displacement detected in the other direction corresponds to a sizable fraction, e.g., one-fourth, of the photosensor array. If there is a sizable fraction, a refresh of the reference image signal is performed using a new, current, image signal. The refresh process is similar to that described above in
FIGS. 6 and 7 . This technique effectively reduces any loss of sensitivity for low-speed displacements either in the x-direction or the y-direction, while ensuring the reference image signal to be at least partly correlated with the new image signal. In addition, as discussed above, the “snapping” effect is also reduced to further increase displacement accuracy. - The present invention beneficially provides for an optical pointing device that has few, if any, mechanical moving parts. The present invention is advantageously capable of operating on a surface capable of diffusely scattering a
collimated beam 305 from a light source having a coherent light component so that a diffusely reflected image of the collimatedbeam 305 can be received by theoptical sensing assembly 260. Moreover, theoptical sensing assembly 260 provides optically matchedoptical elements photosensor arrays illumination spot 390 through the optical elements 310 to be captured and utilized for determining displacement detection for anoptical pointing device 130. In addition, the present invention advantageously provides for 1-D as well as 2-D cross-correlation analysis to determine displacement thereby beneficially reducing computational workloads and reducing overall power consumption. - While particular embodiments and applications of the present invention have been illustrated and described, it is to be understood that the invention is not limited to the precise construction and components disclosed herein and that various modifications, changes and variations which will be apparent to those skilled in the art may be made in the arrangement, operation and details of the method and apparatus of the present invention disclosed herein without departing from the spirit and scope of the invention as defined in the appended claims.
Claims (4)
1. An optical element for use in an optical detection system, the optical element comprising:
a microlens array, including an integrated aperture; and
a beam-shaping structure coupled with the microlens array and configured to direct light in a predetermined direction.
2. The optical element of claim 1 , wherein the microlens array further comprises a diffractive microlens array.
3. The optical element of claim 1 , wherein the microlens array further comprises a refractive microlens array.
4. The optical element of claim 1 wherein the microlens array is geometrically aligned with a photosensor array.
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US11/089,884 US20050168445A1 (en) | 1997-06-05 | 2005-03-25 | Optical detection system, device, and method utilizing optical matching |
Applications Claiming Priority (3)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US08/869,471 US6256016B1 (en) | 1997-06-05 | 1997-06-05 | Optical detection system, device, and method utilizing optical matching |
US09/895,749 US6927758B1 (en) | 1997-06-05 | 2001-06-29 | Optical detection system, device, and method utilizing optical matching |
US11/089,884 US20050168445A1 (en) | 1997-06-05 | 2005-03-25 | Optical detection system, device, and method utilizing optical matching |
Related Parent Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US09/895,749 Continuation US6927758B1 (en) | 1997-06-05 | 2001-06-29 | Optical detection system, device, and method utilizing optical matching |
Publications (1)
Publication Number | Publication Date |
---|---|
US20050168445A1 true US20050168445A1 (en) | 2005-08-04 |
Family
ID=25353600
Family Applications (3)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/869,471 Expired - Lifetime US6256016B1 (en) | 1997-06-05 | 1997-06-05 | Optical detection system, device, and method utilizing optical matching |
US09/895,749 Expired - Lifetime US6927758B1 (en) | 1997-06-05 | 2001-06-29 | Optical detection system, device, and method utilizing optical matching |
US11/089,884 Abandoned US20050168445A1 (en) | 1997-06-05 | 2005-03-25 | Optical detection system, device, and method utilizing optical matching |
Family Applications Before (2)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US08/869,471 Expired - Lifetime US6256016B1 (en) | 1997-06-05 | 1997-06-05 | Optical detection system, device, and method utilizing optical matching |
US09/895,749 Expired - Lifetime US6927758B1 (en) | 1997-06-05 | 2001-06-29 | Optical detection system, device, and method utilizing optical matching |
Country Status (1)
Country | Link |
---|---|
US (3) | US6256016B1 (en) |
Cited By (24)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US20040212593A1 (en) * | 2003-04-23 | 2004-10-28 | Sunplus Technology Co., Ltd. | Optical mechanism of an optical mouse |
US20050231479A1 (en) * | 2004-04-20 | 2005-10-20 | Tong Xie | Illumination spot alignment |
US20060066576A1 (en) * | 2004-09-30 | 2006-03-30 | Microsoft Corporation | Keyboard or other input device using ranging for detection of control piece movement |
US20060125793A1 (en) * | 2004-12-13 | 2006-06-15 | Stephan Hengstler | Apparatus for controlling the position of a screen pointer based on projection data |
US20060213997A1 (en) * | 2005-03-23 | 2006-09-28 | Microsoft Corporation | Method and apparatus for a cursor control device barcode reader |
US20070002013A1 (en) * | 2005-06-30 | 2007-01-04 | Microsoft Corporation | Input device using laser self-mixing velocimeter |
US20070071292A1 (en) * | 2005-09-23 | 2007-03-29 | Siemens Medical Solutions Usa, Inc. | Speckle adaptive medical image processing |
US20070102523A1 (en) * | 2005-11-08 | 2007-05-10 | Microsoft Corporation | Laser velocimetric image scanning |
US20070109267A1 (en) * | 2005-11-14 | 2007-05-17 | Microsoft Corporation | Speckle-based two-dimensional motion tracking |
US20070109268A1 (en) * | 2005-11-14 | 2007-05-17 | Microsoft Corporation | Speckle-based two-dimensional motion tracking |
US20070229461A1 (en) * | 2006-04-04 | 2007-10-04 | Tan Shan C | Optical mouse that automatically adapts to glass surfaces and method of using the same |
US20070291001A1 (en) * | 2006-06-19 | 2007-12-20 | Trisnadi Jahja I | Optical navigation sensor with tracking and lift detection for optically transparent contact surfaces |
US20080030472A1 (en) * | 2006-08-04 | 2008-02-07 | Emcore Corporation | Optical mouse using VCSELS |
DE102006041307A1 (en) * | 2006-09-01 | 2008-03-13 | Sick Ag | Opto-electronic sensor arrangement |
US20080074755A1 (en) * | 2006-09-07 | 2008-03-27 | Smith George E | Lens array imaging with cross-talk inhibiting optical stop structure |
US20080086048A1 (en) * | 2006-05-26 | 2008-04-10 | The Cleveland Clinic Foundation | Method for measuring biomechanical properties in an eye |
US20080259052A1 (en) * | 2007-04-20 | 2008-10-23 | Pixart Imaging Incorporation | Optical touch control apparatus and method thereof |
US20080259050A1 (en) * | 2007-04-20 | 2008-10-23 | Pixart Imaging Incorporation | Optical touch control apparatus and method thereof |
US20090108175A1 (en) * | 2007-10-31 | 2009-04-30 | Grot Annette C | System and method for performing optical navigation using scattered light |
US20110134040A1 (en) * | 2007-09-10 | 2011-06-09 | Jacques Duparre | Optical navigation device |
US9652052B2 (en) * | 2013-06-20 | 2017-05-16 | Pixart Imaging Inc. | Optical mini-mouse |
US11201669B2 (en) | 2018-05-30 | 2021-12-14 | Apple Inc. | Systems and methods for adjusting movable lenses in directional free-space optical communication systems for portable electronic devices |
US11303355B2 (en) * | 2018-05-30 | 2022-04-12 | Apple Inc. | Optical structures in directional free-space optical communication systems for portable electronic devices |
US11549799B2 (en) | 2019-07-01 | 2023-01-10 | Apple Inc. | Self-mixing interference device for sensing applications |
Families Citing this family (136)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6950094B2 (en) | 1998-03-30 | 2005-09-27 | Agilent Technologies, Inc | Seeing eye mouse for a computer system |
US6906699B1 (en) * | 1998-04-30 | 2005-06-14 | C Technologies Ab | Input unit, method for using the same and input system |
US6392632B1 (en) * | 1998-12-08 | 2002-05-21 | Windbond Electronics, Corp. | Optical mouse having an integrated camera |
DE19940217C5 (en) * | 1999-08-25 | 2006-08-10 | Zwick Gmbh & Co | Method for the non-contact measurement of the change in the spatial shape of a test sample, in particular for measuring the change in length of the test sample subjected to an external force and apparatus for carrying out the method |
US6455840B1 (en) | 1999-10-28 | 2002-09-24 | Hewlett-Packard Company | Predictive and pulsed illumination of a surface in a micro-texture navigation technique |
US6766456B1 (en) * | 2000-02-23 | 2004-07-20 | Micron Technology, Inc. | Method and system for authenticating a user of a computer system |
JP2002050778A (en) * | 2000-08-02 | 2002-02-15 | Nippon Sheet Glass Co Ltd | Light-receiving element array, and optical communication monitor module using the same |
US6476970B1 (en) * | 2000-08-10 | 2002-11-05 | Agilent Technologies, Inc. | Illumination optics and method |
US20030098352A1 (en) * | 2000-11-24 | 2003-05-29 | Metrologic Instruments, Inc. | Handheld imaging device employing planar light illumination and linear imaging with image-based velocity detection and aspect ratio compensation |
US7164810B2 (en) * | 2001-11-21 | 2007-01-16 | Metrologic Instruments, Inc. | Planar light illumination and linear imaging (PLILIM) device with image-based velocity detection and aspect ratio compensation |
US6697501B2 (en) * | 2000-11-30 | 2004-02-24 | Vansco Electronics Ltd. | Method for detecting velocity or displacement of an object over a surface by analyzing images of the surface |
KR100399635B1 (en) * | 2000-12-21 | 2003-09-29 | 삼성전기주식회사 | Optical mouse |
KR100399637B1 (en) * | 2000-12-21 | 2003-09-29 | 삼성전기주식회사 | Optical mouse |
US7002549B2 (en) * | 2001-01-18 | 2006-02-21 | Mccahon Stephen William | Optically based machine input control device |
CA2348212A1 (en) * | 2001-05-24 | 2002-11-24 | Will Bauer | Automatic pan/tilt pointing device, luminaire follow-spot, and 6dof 3d position/orientation calculation information gathering system |
US6816154B2 (en) * | 2001-05-30 | 2004-11-09 | Palmone, Inc. | Optical sensor based user interface for a portable electronic device |
US6795056B2 (en) * | 2001-07-24 | 2004-09-21 | Agilent Technologies, Inc. | System and method for reducing power consumption in an optical screen pointing device |
US6847353B1 (en) | 2001-07-31 | 2005-01-25 | Logitech Europe S.A. | Multiple sensor device and method |
TW520481B (en) * | 2001-08-02 | 2003-02-11 | Primax Electronics Ltd | Optical mouse with a ball |
KR100427356B1 (en) * | 2001-08-14 | 2004-04-13 | 삼성전기주식회사 | Sub chip on board for optical mouse |
US7126585B2 (en) * | 2001-08-17 | 2006-10-24 | Jeffery Davis | One chip USB optical mouse sensor solution |
US6770863B2 (en) * | 2001-10-26 | 2004-08-03 | Agilent Technologies, Inc. | Apparatus and method for three-dimensional relative movement sensing |
US6859199B2 (en) * | 2001-11-06 | 2005-02-22 | Omnivision Technologies, Inc. | Method and apparatus for determining relative movement in an optical mouse using feature extraction |
US7042439B2 (en) * | 2001-11-06 | 2006-05-09 | Omnivision Technologies, Inc. | Method and apparatus for determining relative movement in an optical mouse |
US6750846B2 (en) * | 2001-12-05 | 2004-06-15 | Em Microelectronic - Marin Sa | Sensing device for optical pointing devices such as an optical mouse |
US20030187369A1 (en) * | 2002-03-28 | 2003-10-02 | Lewis Stephen B. | Optical pullback sensor for measuring linear displacement of a catheter or other elongate member |
US20030201951A1 (en) * | 2002-04-25 | 2003-10-30 | Unity Opto Technology Co., Ltd. | Wireless optic mouse |
KR100622404B1 (en) * | 2002-10-23 | 2006-09-13 | 주식회사 애트랩 | an optical image detector and optical mouse employing the same |
CN1244044C (en) * | 2003-01-20 | 2006-03-01 | 张宏志 | Mouse optical signal treatment method and device |
JP2004264332A (en) * | 2003-01-24 | 2004-09-24 | Hamamatsu Photonics Kk | Multiplex image formation misalignment detecting device, image density detecting device and multiplex image forming apparatus |
US7418016B2 (en) * | 2003-02-13 | 2008-08-26 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Method and apparatus for modifying the spread of a laser beam |
US7129929B1 (en) * | 2003-03-07 | 2006-10-31 | Microsoft Corporation | Computer input device with multi-purpose light guide |
US7009598B1 (en) * | 2003-03-07 | 2006-03-07 | Microsoft Corporation | Multiple channel light guide for optically tracking pointing and input devices |
US7102626B2 (en) * | 2003-04-25 | 2006-09-05 | Hewlett-Packard Development Company, L.P. | Multi-function pointing device |
CN100337182C (en) * | 2003-05-12 | 2007-09-12 | 凌阳科技股份有限公司 | Optical mechanism improvement for optical mouse |
US7321359B2 (en) * | 2003-07-30 | 2008-01-22 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Method and device for optical navigation |
US20040227954A1 (en) * | 2003-05-16 | 2004-11-18 | Tong Xie | Interferometer based navigation device |
US20040239630A1 (en) * | 2003-05-30 | 2004-12-02 | Ramakrishna Kakarala | Feedback to users of optical navigation devices on non-navigable surfaces |
US7205521B2 (en) * | 2003-07-31 | 2007-04-17 | Avage Technologies Ecbu Ip (Singapore) Pte. Ltd. | Speckle based sensor for three dimensional navigation |
US7227531B2 (en) * | 2003-08-15 | 2007-06-05 | Microsoft Corporation | Data input device for tracking and detecting lift-off from a tracking surface by a reflected laser speckle pattern |
US7161582B2 (en) * | 2003-08-29 | 2007-01-09 | Microsoft Corporation | Data input device for tracking and detecting lift-off from a tracking surface by a reflected laser speckle pattern |
US7359041B2 (en) * | 2003-09-04 | 2008-04-15 | Avago Technologies Ecbu Ip Pte Ltd | Method and system for optically tracking a target using a triangulation technique |
EP1517119B1 (en) * | 2003-09-22 | 2008-04-09 | Xitact S.A. | Optical device for determining the longitudinal and angular position of a rotationally symmetrical apparatus |
KR100516629B1 (en) * | 2003-10-02 | 2005-09-22 | 삼성전기주식회사 | Optical nevigation sensor device and method for processing the image data using the 2-demention sequential process |
TWI225622B (en) * | 2003-10-24 | 2004-12-21 | Sunplus Technology Co Ltd | Method for detecting the sub-pixel motion for optic navigation device |
US7444005B2 (en) * | 2003-11-04 | 2008-10-28 | Becton, Dickinson And Company | Apparatus and method for using optical mouse engine to determine speed, direction, position of scanned device and to obtain quantitative or qualitative data from same |
SE0303370D0 (en) * | 2003-12-16 | 2003-12-16 | Anoto Ab | Method, apparatus, computer program and storage medium for recording a movement of a user unit |
US7221356B2 (en) * | 2004-02-26 | 2007-05-22 | Microsoft Corporation | Data input device and method for detecting an off-surface condition by a laser speckle size characteristic |
US7613329B2 (en) * | 2004-03-08 | 2009-11-03 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Apparatus for controlling the position of a screen pointer that detects defective pixels |
EP1574825A1 (en) * | 2004-03-12 | 2005-09-14 | Xitact S.A. | Device for determining the longitudinal and angular position of a rotationally symmetrical apparatus |
US7474297B2 (en) * | 2004-03-22 | 2009-01-06 | Avago Technologies Ecbu Ip (Singapore) Pte. | Contaminant-resistant optical mouse and cradle |
US7446756B2 (en) * | 2004-03-22 | 2008-11-04 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Apparatus for controlling the position of a screen pointer with low sensitivity to particle contamination |
US7242466B2 (en) * | 2004-03-31 | 2007-07-10 | Microsoft Corporation | Remote pointing system, device, and methods for identifying absolute position and relative movement on an encoded surface by remote optical method |
GB2412715B (en) * | 2004-04-01 | 2008-05-28 | Advanced Input Devices | Improvements Relating to Pointing Devices |
US7292232B2 (en) * | 2004-04-30 | 2007-11-06 | Microsoft Corporation | Data input devices and methods for detecting movement of a tracking surface by a laser speckle pattern |
US20050259097A1 (en) * | 2004-05-21 | 2005-11-24 | Silicon Light Machines Corporation | Optical positioning device using different combinations of interlaced photosensitive elements |
US7773070B2 (en) | 2004-05-21 | 2010-08-10 | Cypress Semiconductor Corporation | Optical positioning device using telecentric imaging |
US20050259078A1 (en) * | 2004-05-21 | 2005-11-24 | Silicon Light Machines Corporation | Optical positioning device with multi-row detector array |
US7315013B2 (en) * | 2004-06-17 | 2008-01-01 | Avago Technologies Ecbu Ip (Singapore) Pte Ltd. | Optical navigation using one-dimensional correlation |
TWI236289B (en) * | 2004-08-11 | 2005-07-11 | Pixart Imaging Inc | Interactive device capable of improving image processing |
US9024880B2 (en) * | 2004-08-11 | 2015-05-05 | Pixart Imaging Inc. | Interactive system capable of improving image processing |
US20090270728A1 (en) * | 2004-12-10 | 2009-10-29 | Intelametrix, Inc. | System for measuring and tracking human body fat |
CN100367168C (en) * | 2004-12-30 | 2008-02-06 | 培新科技股份有限公司 | Light-emitting module of optical mouse |
US7561721B2 (en) * | 2005-02-02 | 2009-07-14 | Visteon Global Technologies, Inc. | System and method for range measurement of a preceding vehicle |
TW200629129A (en) * | 2005-02-04 | 2006-08-16 | Pacing Technology Co Ltd | Optical system with aperture stop for optical mouse and light projection method thereof |
US8212775B2 (en) | 2005-02-22 | 2012-07-03 | Pixart Imaging Incorporation | Computer input apparatus having a calibration circuit for regulating current to the light source |
US20060209015A1 (en) * | 2005-03-18 | 2006-09-21 | Feldmeier David C | Optical navigation system |
US20060209027A1 (en) * | 2005-03-21 | 2006-09-21 | Pixart Imaging, Inc. | Optical mouse with a light-interfering unit |
US20060214909A1 (en) * | 2005-03-23 | 2006-09-28 | Poh Ju C | Vertical cavity surface-emitting laser in non-hermetic transistor outline package |
US20060215720A1 (en) * | 2005-03-24 | 2006-09-28 | Corzine Scott W | Quantum cascade laser with grating formed by a periodic variation in doping |
TWM284968U (en) * | 2005-04-13 | 2006-01-01 | Pixart Imaging Inc | Lens module for optical mouse and related optical module and computer input device |
EP1715406A1 (en) * | 2005-04-23 | 2006-10-25 | STMicroelectronics (Research & Development) Limited | Pointing device and method of operating such a pointing device |
US7889186B2 (en) * | 2005-04-29 | 2011-02-15 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Pen input device and method for tracking pen position |
US20060256086A1 (en) * | 2005-05-12 | 2006-11-16 | Tong Xie | Integrated optical mouse |
TWI275987B (en) * | 2005-05-31 | 2007-03-11 | Pixart Imaging Inc | Optical input device with a light source die mounted on a detecting die and manufacture method thereof |
US7719517B2 (en) * | 2005-06-21 | 2010-05-18 | Microsoft Corporation | Input device for a computer system |
US8179967B2 (en) * | 2005-07-05 | 2012-05-15 | Stmicroelectronics S.A. | Method and device for detecting movement of an entity provided with an image sensor |
US8300015B2 (en) * | 2005-07-05 | 2012-10-30 | Stmicroelectronics S.A. | Method of detecting the movement of an entity equipped with an image sensor and device for implementing same |
US20070031008A1 (en) * | 2005-08-02 | 2007-02-08 | Visteon Global Technologies, Inc. | System and method for range measurement of a preceding vehicle |
US7399954B2 (en) * | 2005-08-16 | 2008-07-15 | Avago Technologies Ecbu Ip Pte Ltd | System and method for an optical navigation device configured to generate navigation information through an optically transparent layer and to have skating functionality |
US7293459B2 (en) * | 2005-09-22 | 2007-11-13 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Image-based sensing of acceleration |
US8917235B2 (en) * | 2005-11-14 | 2014-12-23 | Avago Technologies General Ip (Singapore) Pte. Ltd. | User control input device |
US7623681B2 (en) * | 2005-12-07 | 2009-11-24 | Visteon Global Technologies, Inc. | System and method for range measurement of a preceding vehicle |
US20070139659A1 (en) * | 2005-12-15 | 2007-06-21 | Yi-Yuh Hwang | Device and method for capturing speckles |
US7715016B2 (en) * | 2005-12-15 | 2010-05-11 | Chung Shan Institute Of Science And Technology | Image invariant optical speckle capturing device and method |
US7737948B2 (en) * | 2005-12-20 | 2010-06-15 | Cypress Semiconductor Corporation | Speckle navigation system |
US20070164999A1 (en) * | 2006-01-19 | 2007-07-19 | Gruhlke Russell W | Optical navigation module and lens having large depth of field therefore |
US20070181785A1 (en) * | 2006-02-09 | 2007-08-09 | Helbing Rene P | Compact optical navigation module and microlens array therefore |
US7593833B2 (en) * | 2006-03-03 | 2009-09-22 | At&T Intellectual Property I, L.P. | System and method for determining performance of network lines |
US7557338B2 (en) * | 2006-03-14 | 2009-07-07 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Electronic device with integrated optical navigation module and microlens array therefore |
US8725729B2 (en) * | 2006-04-03 | 2014-05-13 | Steven G. Lisa | System, methods and applications for embedded internet searching and result display |
US20070241271A1 (en) * | 2006-04-14 | 2007-10-18 | Chin Yee L | Reflection-based optical encoders having no code medium |
US20080049972A1 (en) * | 2006-07-07 | 2008-02-28 | Lockheed Martin Corporation | Mail imaging system with secondary illumination/imaging window |
US20080012981A1 (en) * | 2006-07-07 | 2008-01-17 | Goodwin Mark D | Mail processing system with dual camera assembly |
US20080035866A1 (en) * | 2006-07-07 | 2008-02-14 | Lockheed Martin Corporation | Mail imaging system with UV illumination interrupt |
US7728816B2 (en) * | 2006-07-10 | 2010-06-01 | Cypress Semiconductor Corporation | Optical navigation sensor with variable tracking resolution |
US20080030458A1 (en) * | 2006-08-07 | 2008-02-07 | Rene Helbing | Inertial input apparatus and method with optical motion state detection |
US8110787B1 (en) * | 2006-08-23 | 2012-02-07 | ON Semiconductor Trading, Ltd | Image sensor with a reflective waveguide |
US7675020B2 (en) * | 2006-08-28 | 2010-03-09 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Input apparatus and methods having diffuse and specular tracking modes |
US7742514B1 (en) | 2006-10-31 | 2010-06-22 | Cypress Semiconductor Corporation | Laser navigation sensor |
US7868281B2 (en) * | 2006-11-20 | 2011-01-11 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Optical navigation system and method of estimating motion with optical lift detection |
US20080117439A1 (en) * | 2006-11-20 | 2008-05-22 | Yat Kheng Leong | Optical structure, optical navigation system and method of estimating motion |
US7570348B2 (en) * | 2006-12-18 | 2009-08-04 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Methods and apparatus for navigating a surface |
US8730167B2 (en) * | 2007-06-28 | 2014-05-20 | Microsoft Corporation | Pointing device with optical positioning on low-diffusive surfaces |
US20090005948A1 (en) * | 2007-06-28 | 2009-01-01 | Faroog Abdel-Kareem Ibrahim | Low speed follow operation and control strategy |
US8314774B1 (en) | 2007-07-09 | 2012-11-20 | Cypress Semiconductor Corporation | Method and apparatus for quasi-3D tracking using 2D optical motion sensors |
US8263921B2 (en) | 2007-08-06 | 2012-09-11 | Cypress Semiconductor Corporation | Processing methods for speckle-based motion sensing |
US8294082B2 (en) * | 2007-11-14 | 2012-10-23 | Boulder Innovation Group, Inc. | Probe with a virtual marker |
TW200923734A (en) * | 2007-11-23 | 2009-06-01 | Sunplus Mmedia Inc | Coordinate positioning mouse having suspended positioning function |
JP2009139134A (en) * | 2007-12-04 | 2009-06-25 | Ministry Of National Defense Chung Shan Inst Of Science & Technology | Apparatus and method for imaging invariant light spot with large area |
US20090172756A1 (en) * | 2007-12-31 | 2009-07-02 | Motorola, Inc. | Lighting analysis and recommender system for video telephony |
US7924441B1 (en) * | 2008-08-08 | 2011-04-12 | Mirrorcle Technologies, Inc. | Fast and high-precision 3D tracking and position measurement with MEMS micromirrors |
US8541727B1 (en) | 2008-09-30 | 2013-09-24 | Cypress Semiconductor Corporation | Signal monitoring and control system for an optical navigation sensor |
TWI498774B (en) * | 2008-12-04 | 2015-09-01 | Elan Microelectronics Corp | Optical mouse COB module and the optical mouse |
KR101019173B1 (en) * | 2008-12-09 | 2011-03-04 | 국방부 군비국 중산 과학 연구원 | Large area undistorted imaging apparatus for optical speckles and method thereof |
CN101751148B (en) * | 2008-12-10 | 2012-04-11 | 徐克铭 | Capturing device and capturing method for non-deformable light spots |
US8217334B1 (en) * | 2008-12-24 | 2012-07-10 | Cypress Semiconductor Corporation | Optical navigation sensor including a spatial frequency filter |
US8711096B1 (en) | 2009-03-27 | 2014-04-29 | Cypress Semiconductor Corporation | Dual protocol input device |
KR101106409B1 (en) * | 2009-07-10 | 2012-01-17 | 엘지전자 주식회사 | Plasma lighting system and controlling method the same |
US8269723B2 (en) * | 2010-01-06 | 2012-09-18 | Sunrex Technology Corp. | Computer mouse with virtual keys |
DE102010015014A1 (en) | 2010-04-14 | 2011-10-20 | Bayer Technology Services Gmbh | Optical scanner |
US8576402B2 (en) | 2010-07-22 | 2013-11-05 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Optical navigation with specular reflection blocking |
US8317104B2 (en) | 2010-08-05 | 2012-11-27 | Hand Held Products, Inc. | Image engine with integrated circuit structure for indicia reading terminal |
US8692880B2 (en) | 2010-10-05 | 2014-04-08 | Mitutoyo Corporation | Image correlation displacement sensor |
US8605291B2 (en) | 2010-12-01 | 2013-12-10 | Mitutoyo Corporation | Image correlation displacement sensor |
EP2649505B1 (en) * | 2010-12-08 | 2019-06-05 | Nokia Technologies Oy | User interface |
US8546741B2 (en) * | 2011-01-13 | 2013-10-01 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Compact optical finger navigation system based on speckles with an optical element including an optical redirection surface |
US8687172B2 (en) | 2011-04-13 | 2014-04-01 | Ivan Faul | Optical digitizer with improved distance measurement capability |
US9703396B2 (en) * | 2013-07-12 | 2017-07-11 | Wen-Chieh Geoffrey Lee | High resolution and high sensitivity three-dimensional (3D) cursor maneuvering reference plane, and methods of its manufacture |
US10075246B2 (en) * | 2013-09-26 | 2018-09-11 | Micro Motion, Inc. | Optical isolator mounted in printed circuit board recess |
US10267675B2 (en) | 2014-12-05 | 2019-04-23 | Monash University | Multi-directional optical receiver |
JP2017102381A (en) * | 2015-12-04 | 2017-06-08 | オリンパス株式会社 | Microscope system |
US10627518B2 (en) * | 2017-06-02 | 2020-04-21 | Pixart Imaging Inc | Tracking device with improved work surface adaptability |
CN108007352B (en) * | 2018-01-05 | 2024-03-15 | 洛阳理工学院 | Foot stress measuring device based on digital speckle correlation technology |
EP3928282A4 (en) * | 2019-02-18 | 2022-04-13 | Fingerprint Cards Anacatum IP AB | Optical biometric imaging device and method of operating an optical biometric imaging device |
CN116679834B (en) * | 2023-08-02 | 2023-10-24 | 南昌大藏科技有限公司 | Large-space multi-person VR interactive experience system and method |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5684566A (en) * | 1995-05-24 | 1997-11-04 | Svg Lithography Systems, Inc. | Illumination system and method employing a deformable mirror and diffractive optical elements |
US5686720A (en) * | 1995-03-02 | 1997-11-11 | Hewlett Packard Company | Method and device for achieving high contrast surface illumination |
US6218659B1 (en) * | 1992-10-05 | 2001-04-17 | Logitech, Inc. | Dual layer optical ball for pointing device |
Family Cites Families (74)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5164579A (en) * | 1979-04-30 | 1992-11-17 | Diffracto Ltd. | Method and apparatus for electro-optically determining the dimension, location and attitude of objects including light spot centroid determination |
US4334780A (en) * | 1979-06-29 | 1982-06-15 | Grumman Aerospace Corporation | Optical surface roughness detection method and apparatus |
US4521773A (en) | 1981-08-28 | 1985-06-04 | Xerox Corporation | Imaging array |
US4521772A (en) | 1981-08-28 | 1985-06-04 | Xerox Corporation | Cursor control device |
JPS5948668A (en) | 1982-09-13 | 1984-03-19 | Jiro Koyama | Optical fiber speedometer |
US4611912A (en) | 1983-04-04 | 1986-09-16 | Ball Corporation | Method and apparatus for optically measuring distance and velocity |
KR920002254B1 (en) | 1983-12-05 | 1992-03-20 | 닛신 고오기 가부시끼가이샤 | Optical mouse |
JPS60183863A (en) | 1984-03-02 | 1985-09-19 | Fujitsu Ltd | Holding system of telephone set |
JPS60183862A (en) | 1984-03-02 | 1985-09-19 | Toshiba Corp | Digital signal processing circuit |
US4626103A (en) | 1984-03-29 | 1986-12-02 | At&T Bell Laboratories | Focus tracking system |
US4799055A (en) | 1984-04-26 | 1989-01-17 | Symbolics Inc. | Optical Mouse |
US4794384A (en) | 1984-09-27 | 1988-12-27 | Xerox Corporation | Optical translator device |
JPS6195431A (en) | 1984-10-17 | 1986-05-14 | Matsushita Electric Ind Co Ltd | Input device of positional information |
CA1266562A (en) | 1986-09-24 | 1990-03-13 | Donald Stewart | Distance measuring apparatus |
JPS63144206A (en) | 1986-12-08 | 1988-06-16 | Minolta Camera Co Ltd | Measuring method for body position |
US5114226A (en) | 1987-03-20 | 1992-05-19 | Digital Optronics Corporation | 3-Dimensional vision system utilizing coherent optical detection |
US5363120A (en) * | 1987-10-14 | 1994-11-08 | Wang Laboratories, Inc. | Computer input device using orientation sensor |
JP2668937B2 (en) | 1988-05-16 | 1997-10-27 | 富士ゼロックス株式会社 | Positioning device |
JPH01287468A (en) | 1988-05-16 | 1989-11-20 | Fuji Xerox Co Ltd | Moving information detecting method for random space pattern |
US5793032A (en) | 1991-11-04 | 1998-08-11 | Symbol Technologies, Inc. | Portable optical scanning and pointing systems |
US5015835A (en) | 1988-12-23 | 1991-05-14 | Ricoh Company, Ltd. | Optical information reading and writing device with diffraction means |
US5015070A (en) | 1989-03-14 | 1991-05-14 | Mouse Systems Corporation | Reference grid for optical scanner |
US5056080A (en) * | 1989-09-22 | 1991-10-08 | Russell James T | Optical recording/reproducing system using interference techniques |
JPH03111762A (en) | 1989-09-26 | 1991-05-13 | Omron Corp | Speckle speed sensor |
JPH03249870A (en) | 1989-10-31 | 1991-11-07 | Kuraray Co Ltd | Pad for optical reader |
US5241167A (en) * | 1990-11-07 | 1993-08-31 | Canon Kabushiki Kaisha | Photosensor device including means for designating a plurality of pixel blocks of any desired size |
US5362940A (en) * | 1990-11-09 | 1994-11-08 | Litel Instruments | Use of Fresnel zone plates for material processing |
US5274361A (en) | 1991-08-15 | 1993-12-28 | The United States Of America As Represented By The Secretary Of The Navy | Laser optical mouse |
JPH05233139A (en) | 1992-02-21 | 1993-09-10 | Nhk Spring Co Ltd | Computer input device |
US5319182A (en) * | 1992-03-04 | 1994-06-07 | Welch Allyn, Inc. | Integrated solid state light emitting and detecting array and apparatus employing said array |
US5420943A (en) | 1992-04-13 | 1995-05-30 | Mak; Stephen M. | Universal computer input device |
US5680157A (en) | 1992-08-10 | 1997-10-21 | Logitech, Inc. | Pointing device with differential optomechanical sensing |
US5340978A (en) * | 1992-09-30 | 1994-08-23 | Lsi Logic Corporation | Image-sensing display panels with LCD display panel and photosensitive element array |
US5907152A (en) * | 1992-10-05 | 1999-05-25 | Logitech, Inc. | Pointing device utilizing a photodetector array |
US5729009A (en) | 1992-10-05 | 1998-03-17 | Logitech, Inc. | Method for generating quasi-sinusoidal signals |
US6031218A (en) | 1992-10-05 | 2000-02-29 | Logitech, Inc. | System and method for generating band-limited quasi-sinusoidal signals |
US5854482A (en) | 1992-10-05 | 1998-12-29 | Logitech, Inc. | Pointing device utilizing a photodector array |
US5288993A (en) * | 1992-10-05 | 1994-02-22 | Logitech, Inc. | Cursor pointing device utilizing a photodetector array with target ball having randomly distributed speckles |
US6084574A (en) | 1992-10-05 | 2000-07-04 | Logitech, Inc. | Compact cursor pointing device utilizing photodetector array |
US5793357A (en) * | 1992-11-14 | 1998-08-11 | Ivey; Peter Anthony | Device and method for determining movement of a surface |
GB2272763B (en) | 1992-11-14 | 1996-04-24 | Univ Sheffield | Device and method for determining movement |
JP3083019B2 (en) | 1993-03-05 | 2000-09-04 | キヤノン株式会社 | Optical device and speed information detecting device |
US5525764A (en) * | 1994-06-09 | 1996-06-11 | Junkins; John L. | Laser scanning graphic input system |
US5610705A (en) | 1995-02-16 | 1997-03-11 | Northrop Grumman Corporation | Doppler velocimeter |
US5578813A (en) | 1995-03-02 | 1996-11-26 | Allen; Ross R. | Freehand image scanning device which compensates for non-linear movement |
CN1090362C (en) | 1995-03-15 | 2002-09-04 | 皇家菲利浦电子有限公司 | Device for optically scanning recording medium |
JP2725632B2 (en) | 1995-05-24 | 1998-03-11 | 日本電気株式会社 | Optical head device |
US5786804A (en) | 1995-10-06 | 1998-07-28 | Hewlett-Packard Company | Method and system for tracking attitude |
JPH09190277A (en) | 1996-01-12 | 1997-07-22 | Sony Corp | Input device |
US5729008A (en) | 1996-01-25 | 1998-03-17 | Hewlett-Packard Company | Method and device for tracking relative movement by correlating signals from an array of photoelements |
US5769384A (en) | 1996-01-25 | 1998-06-23 | Hewlett-Packard Company | Low differential light level photoreceptors |
US5703353A (en) | 1996-01-25 | 1997-12-30 | Hewlett-Packard Company | Offset removal and spatial frequency band filtering circuitry for photoreceiver signals |
US6040592A (en) | 1997-06-12 | 2000-03-21 | Intel Corporation | Well to substrate photodiode for use in a CMOS sensor on a salicide process |
US6040950A (en) | 1998-01-05 | 2000-03-21 | Intel Corporation | Athermalized mounts for lenses |
US6172354B1 (en) | 1998-01-28 | 2001-01-09 | Microsoft Corporation | Operator input device |
US6104020A (en) | 1998-02-17 | 2000-08-15 | Agilent Technologies | Electronic shutter for a low differential light level photo-receiver cell |
US6233368B1 (en) | 1998-03-18 | 2001-05-15 | Agilent Technologies, Inc. | CMOS digital optical navigation chip |
US6049338A (en) | 1998-04-01 | 2000-04-11 | Hewlett-Packard Company | Spatial filter for surface texture navigation |
US6151015A (en) | 1998-04-27 | 2000-11-21 | Agilent Technologies | Pen like computer pointing device |
US6057540A (en) | 1998-04-30 | 2000-05-02 | Hewlett-Packard Co | Mouseless optical and position translation type screen pointer control for a computer system |
US5994710A (en) | 1998-04-30 | 1999-11-30 | Hewlett-Packard Company | Scanning mouse for a computer system |
US5940217A (en) | 1998-05-06 | 1999-08-17 | Intel Corporation | Anti-aliasing diffractive aperture and optical system using the same |
US6021009A (en) | 1998-06-30 | 2000-02-01 | Intel Corporation | Method and apparatus to improve across field dimensional control in a microlithography tool |
US6002525A (en) | 1998-07-06 | 1999-12-14 | Intel Corporation | Correcting lens distortion |
US6188057B1 (en) | 1998-09-11 | 2001-02-13 | Agilent Technologies, Inc. | Method and apparatus for testing photo-receiver arrays and associated read channels |
US6222182B1 (en) | 1998-11-30 | 2001-04-24 | Microsoft Corporation | Apparatus and method for sampling a phototransistor |
US6303924B1 (en) | 1998-12-21 | 2001-10-16 | Microsoft Corporation | Image sensing operator input device |
US5952997A (en) | 1999-02-19 | 1999-09-14 | Hu; Ken-Pei | Encoder wheel arrangement |
US6531692B1 (en) | 1999-03-22 | 2003-03-11 | Microsoft Corporation | Optical coupling assembly for image sensing operator input device |
US6683598B1 (en) | 1999-09-01 | 2004-01-27 | Microsoft Corporation | Mouse optical sampling scheme |
US6380927B1 (en) | 1999-11-17 | 2002-04-30 | Microsoft Corporation | Determining the position of a detented optical encoder |
US6462330B1 (en) | 2000-03-24 | 2002-10-08 | Microsoft Corporation | Cover with integrated lens for integrated chip optical sensor |
EP1182606A2 (en) | 2000-07-31 | 2002-02-27 | Agilent Technologies, Inc. (a Delaware corporation) | Four axis optical mouse |
US6664948B2 (en) | 2001-07-30 | 2003-12-16 | Microsoft Corporation | Tracking pointing device motion using a single buffer for cross and auto correlation determination |
-
1997
- 1997-06-05 US US08/869,471 patent/US6256016B1/en not_active Expired - Lifetime
-
2001
- 2001-06-29 US US09/895,749 patent/US6927758B1/en not_active Expired - Lifetime
-
2005
- 2005-03-25 US US11/089,884 patent/US20050168445A1/en not_active Abandoned
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US6218659B1 (en) * | 1992-10-05 | 2001-04-17 | Logitech, Inc. | Dual layer optical ball for pointing device |
US5686720A (en) * | 1995-03-02 | 1997-11-11 | Hewlett Packard Company | Method and device for achieving high contrast surface illumination |
US5684566A (en) * | 1995-05-24 | 1997-11-04 | Svg Lithography Systems, Inc. | Illumination system and method employing a deformable mirror and diffractive optical elements |
Cited By (45)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US7071923B2 (en) * | 2003-04-23 | 2006-07-04 | Sunplus Technology Co., Ltd. | Optical mechanism of an optical mouse |
US20040212593A1 (en) * | 2003-04-23 | 2004-10-28 | Sunplus Technology Co., Ltd. | Optical mechanism of an optical mouse |
US8325140B2 (en) * | 2004-04-20 | 2012-12-04 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | Illumination spot alignment |
US20050231479A1 (en) * | 2004-04-20 | 2005-10-20 | Tong Xie | Illumination spot alignment |
US20060066576A1 (en) * | 2004-09-30 | 2006-03-30 | Microsoft Corporation | Keyboard or other input device using ranging for detection of control piece movement |
US7528824B2 (en) | 2004-09-30 | 2009-05-05 | Microsoft Corporation | Keyboard or other input device using ranging for detection of control piece movement |
US20060125793A1 (en) * | 2004-12-13 | 2006-06-15 | Stephan Hengstler | Apparatus for controlling the position of a screen pointer based on projection data |
US7379049B2 (en) * | 2004-12-13 | 2008-05-27 | Avago Technologies Ecbu Ip Pte Ltd | Apparatus for controlling the position of a screen pointer based on projection data |
US20060213997A1 (en) * | 2005-03-23 | 2006-09-28 | Microsoft Corporation | Method and apparatus for a cursor control device barcode reader |
US20070002013A1 (en) * | 2005-06-30 | 2007-01-04 | Microsoft Corporation | Input device using laser self-mixing velocimeter |
US7557795B2 (en) | 2005-06-30 | 2009-07-07 | Microsoft Corporation | Input device using laser self-mixing velocimeter |
US20070071292A1 (en) * | 2005-09-23 | 2007-03-29 | Siemens Medical Solutions Usa, Inc. | Speckle adaptive medical image processing |
US7983456B2 (en) * | 2005-09-23 | 2011-07-19 | Siemens Medical Solutions Usa, Inc. | Speckle adaptive medical image processing |
US7543750B2 (en) | 2005-11-08 | 2009-06-09 | Microsoft Corporation | Laser velocimetric image scanning |
US20070102523A1 (en) * | 2005-11-08 | 2007-05-10 | Microsoft Corporation | Laser velocimetric image scanning |
US20070109268A1 (en) * | 2005-11-14 | 2007-05-17 | Microsoft Corporation | Speckle-based two-dimensional motion tracking |
US20070109267A1 (en) * | 2005-11-14 | 2007-05-17 | Microsoft Corporation | Speckle-based two-dimensional motion tracking |
US7505033B2 (en) * | 2005-11-14 | 2009-03-17 | Microsoft Corporation | Speckle-based two-dimensional motion tracking |
US20070229461A1 (en) * | 2006-04-04 | 2007-10-04 | Tan Shan C | Optical mouse that automatically adapts to glass surfaces and method of using the same |
US7760186B2 (en) * | 2006-04-04 | 2010-07-20 | Avago Technologies General Ip (Singapore) Pte. Ltd. | Optical mouse that automatically adapts to glass surfaces and method of using the same |
US7935058B2 (en) * | 2006-05-26 | 2011-05-03 | The Cleveland Clinic Foundation | Method for measuring biomechanical properties in an eye |
US20080086048A1 (en) * | 2006-05-26 | 2008-04-10 | The Cleveland Clinic Foundation | Method for measuring biomechanical properties in an eye |
WO2007149222A3 (en) * | 2006-06-19 | 2008-04-17 | Silicon Light Machines Corp | Optical navigation sensor with tracking and lift detection for optically transparent contact surfaces |
US20070291001A1 (en) * | 2006-06-19 | 2007-12-20 | Trisnadi Jahja I | Optical navigation sensor with tracking and lift detection for optically transparent contact surfaces |
US7755604B2 (en) * | 2006-06-19 | 2010-07-13 | Cypress Semiconductor Corporation | Optical navigation sensor with tracking and lift detection for optically transparent contact surfaces |
WO2007149222A2 (en) * | 2006-06-19 | 2007-12-27 | Silicon Light Machines Corporation | Optical navigation sensor with tracking and lift detection for optically transparent contact surfaces |
US7791591B2 (en) * | 2006-08-04 | 2010-09-07 | Emcore Corporation | Optical mouse using VCSELs |
US20080030472A1 (en) * | 2006-08-04 | 2008-02-07 | Emcore Corporation | Optical mouse using VCSELS |
US7936450B2 (en) | 2006-09-01 | 2011-05-03 | Sick Ag | Opto-electrical sensor arrangement |
DE102006041307A1 (en) * | 2006-09-01 | 2008-03-13 | Sick Ag | Opto-electronic sensor arrangement |
US20080074642A1 (en) * | 2006-09-01 | 2008-03-27 | Ingolf Hoersch | Opto-electrical sensor arrangement |
US7408718B2 (en) * | 2006-09-07 | 2008-08-05 | Avago Technologies General Pte Ltd | Lens array imaging with cross-talk inhibiting optical stop structure |
US20080074755A1 (en) * | 2006-09-07 | 2008-03-27 | Smith George E | Lens array imaging with cross-talk inhibiting optical stop structure |
US8325154B2 (en) * | 2007-04-20 | 2012-12-04 | Pixart Imaging Incorporation | Optical touch control apparatus and method thereof |
US20080259050A1 (en) * | 2007-04-20 | 2008-10-23 | Pixart Imaging Incorporation | Optical touch control apparatus and method thereof |
US20080259052A1 (en) * | 2007-04-20 | 2008-10-23 | Pixart Imaging Incorporation | Optical touch control apparatus and method thereof |
US20110134040A1 (en) * | 2007-09-10 | 2011-06-09 | Jacques Duparre | Optical navigation device |
US8138488B2 (en) * | 2007-10-31 | 2012-03-20 | Avago Technologies Ecbu Ip (Singapore) Pte. Ltd. | System and method for performing optical navigation using scattered light |
JP2009176276A (en) * | 2007-10-31 | 2009-08-06 | Avago Technologies Ecbu Ip (Singapore) Pte Ltd | System and method for performing optical navigation using scattered light |
US20090108175A1 (en) * | 2007-10-31 | 2009-04-30 | Grot Annette C | System and method for performing optical navigation using scattered light |
US9652052B2 (en) * | 2013-06-20 | 2017-05-16 | Pixart Imaging Inc. | Optical mini-mouse |
US11201669B2 (en) | 2018-05-30 | 2021-12-14 | Apple Inc. | Systems and methods for adjusting movable lenses in directional free-space optical communication systems for portable electronic devices |
US11303355B2 (en) * | 2018-05-30 | 2022-04-12 | Apple Inc. | Optical structures in directional free-space optical communication systems for portable electronic devices |
US11870492B2 (en) | 2018-05-30 | 2024-01-09 | Apple Inc. | Optical structures in directional free-space optical communication systems for portable electronic devices |
US11549799B2 (en) | 2019-07-01 | 2023-01-10 | Apple Inc. | Self-mixing interference device for sensing applications |
Also Published As
Publication number | Publication date |
---|---|
US6256016B1 (en) | 2001-07-03 |
US6927758B1 (en) | 2005-08-09 |
Similar Documents
Publication | Publication Date | Title |
---|---|---|
US6256016B1 (en) | Optical detection system, device, and method utilizing optical matching | |
US7321359B2 (en) | Method and device for optical navigation | |
US7505033B2 (en) | Speckle-based two-dimensional motion tracking | |
KR101192909B1 (en) | Position detection system using laser speckle | |
US6225617B1 (en) | Method for generating quasi-sinusoidal signals | |
US7042575B2 (en) | Speckle sizing and sensor dimensions in optical positioning device | |
US20070126700A1 (en) | Method and apparatus for sensing motion of a user interface mechanism using optical navigation technology | |
US5907152A (en) | Pointing device utilizing a photodetector array | |
US7737948B2 (en) | Speckle navigation system | |
US8345003B1 (en) | Optical positioning device using telecentric imaging | |
US7593113B2 (en) | Large areas undistorted imaging apparatus for light speckles and method thereof | |
WO2019076072A1 (en) | Optical distance measurement method and apparatus | |
WO1994011845A1 (en) | Device and method for determining movement of a surface | |
KR100905382B1 (en) | Method for processing optical signals in a computer mouse | |
NL9301709A (en) | Pointing device provided with a photodetector matrix. | |
US7285766B2 (en) | Optical positioning device having shaped illumination | |
US7746477B1 (en) | System and method for illuminating and imaging a surface for an optical navigation system | |
WO2005114643A2 (en) | Optical positioning device using telecentric imaging | |
CN112525078B (en) | Three-dimensional measuring device and operation method thereof | |
US8259069B1 (en) | Speckle-based optical navigation on curved tracking surface | |
JP2001331264A (en) | Optical position detecting device and optical position detecting method | |
WO2005114097A2 (en) | Speckle sizing and sensor dimensions in optical positioning device | |
KR20070026614A (en) | Optical positioning device having shaped illumination |
Legal Events
Date | Code | Title | Description |
---|---|---|---|
STCB | Information on status: application discontinuation |
Free format text: ABANDONED -- FAILURE TO RESPOND TO AN OFFICE ACTION |