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Publication numberUS20080287207 A1
Publication typeApplication
Application numberUS 11/841,170
Publication dateNov 20, 2008
Filing dateAug 20, 2007
Priority dateAug 27, 2003
Publication number11841170, 841170, US 2008/0287207 A1, US 2008/287207 A1, US 20080287207 A1, US 20080287207A1, US 2008287207 A1, US 2008287207A1, US-A1-20080287207, US-A1-2008287207, US2008/0287207A1, US2008/287207A1, US20080287207 A1, US20080287207A1, US2008287207 A1, US2008287207A1
InventorsScott R. Manwaring
Original AssigneeCallaway Golf Company
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
System and method for measuring a golfer's ball striking parameters
US 20080287207 A1
Abstract
A system (20) for capturing and analyzing golf club information and golf ball information during and after a golfer's swing is disclosed herein. The golf club information includes golf club head orientation, golf club head velocity, and golf club spin. The golf club head orientation includes dynamic lie, loft and face angle of the golf club head. The golf club head velocity includes path of the golf club head, attack of the golf club head and downrange information. The golf ball information includes golf ball velocity, golf ball launch angle, golf ball side angle, golf ball speed manipulation and golf ball orientation. The golf ball orientation includes the true spin of the golf ball, and the tilt axis of the golf ball which entails the back spin and the side spin of the golf ball. The system includes CMOS camera units (26 and 28) and a computer (22).
Images(27)
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Claims(8)
1. A method for measuring a golfer's ball striking properties, the method comprising:
monitoring a field of view for detection of an object, the object being a golf club or a golf ball;
detecting the object within the field view;
creating a first region of interest within the field of view, the region of interest encompassing the object;
tracking the movement of the object in the field of view with a plurality of regions of interest;
creating of a plurality of images from each of the plurality of regions of interest;
obtaining a golfer's ball striking properties from the plurality of images.
2. A method for measuring a golfer's ball striking properties using a CMOS based imaging system, the method comprising:
monitoring a sensor array for detection of an object, the sensor array composed of at least one million active pixels;
detecting an object having a threshold brightness within the sensor array;
creating a first region of interest within the field of view, the region of interest encompassing the object;
tracking the movement of the object in the field of view with a plurality of regions of interest;
creating of a plurality of images from each of the plurality of regions of interest;
obtaining a golfer's ball striking properties from the plurality of images.
3. A method for measuring a golfer's ball striking properties using a CMOS based imaging system, the method comprising:
generating an image of a field of view at a frame rate of 250 to 500 frames per second to monitor for detection of an object, the field of view corresponding to a CMOS sensor array composed of at least one million active pixels, the object being a golf club or golf ball;
detecting an object having a threshold brightness within the field of view;
creating a region of interest within the field of view, the region of interest encompassing the object, the region of interest corresponding to a plurality of active pixels of the CMOS sensor array;
tracking the object through the field of view with a plurality of overlapping regions of interest that encompass the object, each of the plurality of overlapping regions of interest corresponding to a plurality of active pixels of the CMOS sensor array; and
analyzing the plurality of regions of interest to obtain swing properties for the golf club or launch parameters for the golf ball.
4. A method for measuring a golfer's ball striking properties using a CMOS based imaging system, the method comprising:
generating an image of a field of view at a frame rate of 250 to 500 frames per second to monitor for detection of an object, the field of view corresponding to a CMOS sensor array composed of at least one million active pixels, the object being a golf club or golf ball;
detecting an object having a threshold brightness within the field of view;
creating a region of interest within the field of view, the region of interest encompassing the object, the region of interest corresponding to a plurality of active pixels of the CMOS sensor array;
tracking the object through the field of view with a plurality of overlapping regions of interest that encompass the object, each of the plurality of overlapping regions of interest corresponding to a plurality of active pixels of the CMOS sensor array; and
analyzing the plurality of regions of interest to obtain swing properties for the golf club or launch parameters for the golf ball.
5. A method for simultaneously measuring the golf club properties and the golf ball properties during a golfer's striking of a golf ball, the method comprising:
swinging a golf club toward a teed golf ball;
activating an imaging system, the imaging system capable of compiling a plurality of images;
taking a first plurality of images of the golf club head prior to the golf club head impacting the teed golf ball;
striking the teed golf ball with the golf club;
taking a second plurality of images of the golf ball after the golf ball has been struck by the golf club head;
wherein the method provides measurements of the golf club head and of the launched golf ball.
6. The method according to claim 1 wherein the imaging system comprises a first CMOS camera and a second CMOS camera.
7. A system simultaneously measuring the golf club properties and the golf ball properties during a golfer's striking of a golf ball, the system comprising:
a first CMOS camera and a second CMOS camera, each of the first and second cameras focused toward a predetermined field view;
a golf club having at least one light contrasting area thereon;
a golf ball teed within the predetermined field of view; and
means for determining the golf club swing properties and golf ball launch properties based on images generated by the first and second CMOS cameras.
8. A method for using a CMOS imaging system to determine golf club swing properties and golf ball launch properties.
Description
CROSS REFERENCES TO RELATED APPLICATIONS

The Present Application is a continuation of U.S. patent application Ser. No. 10/843048, filed on May 10, 2004, which claims priority to U.S. Provisional Application No. 60/498,469 filed on Aug. 27, 2003, now abandoned.

STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not Applicable

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system and method for measuring a golfer's swing parameters during a golf swing. More specifically, the present invention relates to a system and method for measuring club head information and golf ball information before and after impact of the golf club with the golf ball.

2. Description of the Related Art

For over twenty-five years, high speed camera technology has been used for gathering information on a golfer's swing. The information has varied from simple club head speed to the spin of the golf ball after impact with a certain golf club. Over the years, this information has fostered numerous improvements in golf clubs and golf balls, and assisted golfers in choosing golf clubs and golf balls that improve their game. Additionally, systems incorporating such high speed camera technology have been used in teaching golfers how to improve their swing when using a given golf club.

An example of such a system is U.S. Pat. No. 4,063,259 to Lynch et al., for a Method Of Matching Golfer With Golf Ball, Golf Club, Or Style Of Play, which was filed in 1975. Lynch discloses a system that provides golf ball launch measurements through use of a shuttered camera that is activated when a club head breaks a beam of light that activates the flashing of a light source to provide stop action of the club head and golf ball on a camera film. The golf ball launch measurements retrieved by the Lynch system include initial velocity, initial spin velocity and launch angle.

Another example is U.S. Pat. No. 4,136,387 to Sullivan, et al., for a Golf Club Impact And Golf Ball Launching Monitoring System, which was filed in 1977. Sullivan discloses a system that not only provides golf ball launch measurements, it also provides measurements on the golf club.

Yet another example is a family of patent to Gobush et al., U.S. Pat. Nos. 5,471,383 filed on Sep. 30, 1994; 5,501,463 filed on Feb. 24, 1994; 5,575,719 filed on Aug. 1, 1995; and 5,803,823 filed on Nov. 18, 1996. This family of patents discloses a system that has two cameras angled toward each other, a golf ball with reflective markers, a golf club with reflective markers thereon and a computer. The system allows for measurement of the golf club or golf ball separately, based on the plotting of points.

Yet another example is U.S. Pat. No. 6,042,483 for a Method Of Measuring Motion Of A Golf Ball. The patent discloses a system that uses three cameras, an optical sensor means, and strobes to obtain golf club and golf ball information.

Many current ball launch monitors utilize CCD (charge coupled device) cameras to obtain images to analyze a golfer's swing parameters. A CCD camera is limited to a set field of view, and also has limitations as to the number of images that can be obtained within a second.

BRIEF SUMMARY OF THE INVENTION

The present invention provides a method and system for capturing and analyzing golf club information and golf ball information during and after a golfer's swing is disclosed herein. The golf club information includes golf club head orientation, golf club head velocity, and golf club spin. The golf club head orientation includes dynamic lie, loft and face angle of the golf club head. The golf club head velocity includes path of the golf club head and attack of the golf club head. The golf ball information includes golf ball velocity, golf ball launch angle, golf ball side angle, golf ball speed and golf ball orientation. The golf ball orientation includes the true spin of the golf ball, and the tilt axis of the golf ball which entails the back spin and the side spin of the golf ball.

One aspect of the present invention is a system for simultaneously measuring the golf club properties and the golf ball properties during a golfer's striking of a golf ball. The system includes a pair of CMOS cameras, a golf club, a golf ball, a calculating means and an analysis means. The first and second CMOS cameras each have a lens focused toward a predetermined field of view. The golf club has at least one light contrasting area, and preferably three light contrasting areas. The golf ball is within the predetermined field of view. The analysis means determines the golf club swing properties and golf ball launch properties based on an images generated by the first and second CMOS cameras.

Having briefly described the present invention, the above and further objects, features and advantages thereof will be recognized by those skilled in the pertinent art from the following detailed description of the invention when taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

FIG. 1 is a perspective view of the monitoring system of the present invention.

FIG. 2 is a schematic isolated side view of the teed golf ball and the cameras of the system of the present invention.

FIG. 2A is a schematic isolated side view of the teed golf ball and the cameras of the system showing the field of view of the cameras.

FIG. 3 is a schematic isolated front view of the teed golf ball, trigger device and the cameras of the system of the present invention.

FIG. 4 is a schematic representation of a full frame CMOS sensor array.

FIG. 5 is a schematic representation of a field of view.

FIG. 6 a schematic representation of a ROI within the CMOS sensor array.

FIG. 7 a schematic representation of an object within the field of view.

FIG. 8 a schematic representation of an object within the field of view.

FIG. 9 a schematic representation of a ROI within the CMOS sensor array.

FIG. 10 a schematic representation of an object within the field of view.

FIG. 11 a schematic representation of a ROI within the CMOS sensor array.

FIG. 12 a schematic representation of an object within the field of view.

FIG. 13 a schematic representation of a ROI within the CMOS sensor array.

FIG. 14 is a flow chart of a method of using the system of the invention.

FIG. 15 is a flow chart of a method of using the system of the invention.

FIG. 16 is a flow chart of a method of using the system of the invention.

FIG. 17 is a flow chart of a method of using the system of the invention.

FIG. 18 is a flow chart of a method of using the system of the invention.

FIG. 19 is a schematic representation of the highly reflective points of the golf club positioned in accordance with the first, second and third exposures of the golf club.

FIG. 20 is an isolated view of a golf ball striped for measurement.

FIG. 20A is an isolated view of a golf ball striped for measurement using an image with a partial phantom of a prior image with vector signs present to demonstrate calculation of angle θ.

FIG. 21 illustrates first, second and third images of the connected highly reflective points on a golf club, and the teed golf ball for the first find grouping of the highly reflective points.

FIG. 21A illustrates first, second and third images of the connected highly reflective points on a golf club, and the teed golf ball for the first find grouping of the highly reflective points.

FIG. 22 illustrates first, second and third images of the connected highly reflective points on a golf club, and the teed golf ball for the second find grouping of the highly reflective points.

FIG. 23 illustrates first, second and third images of the connected highly reflective points on a golf club, and the teed golf ball for the second find grouping of the highly reflective points.

FIG. 24 illustrates first, second and third images of the connected highly reflective points on a golf club, and the teed golf ball with repeated points eliminated and results of the find displayed.

FIG. 25 illustrates first, second and third images of the connected highly reflective points on a golf club, and the teed golf ball with repeated points eliminated and results of the find displayed.

FIG. 26 is a chart of the processed final pairs giving the x, y and z coordinates.

FIG. 27 is an illustration of the images for the golf ball in flight.

FIG. 28 is an isolated view of the golf ball to illustrate determining the best ball center and radius.

FIG. 29 is a partial flow chart with images of golf balls for stereo correlating two dimensional points.

FIG. 30 illustrates the teed golf ball and the first, second, third and fourth images of the golf ball after impact, along with positioning information.

DETAILED DESCRIPTION OF THE INVENTION

As shown in FIGS. 1-3, the system of the present invention is generally designated 20. The system 20 captures and analyzes golf club information and golf ball information during and after a golfer's swing. The golf club information includes golf club head orientation, golf club head velocity, and golf club spin. The golf club head orientation includes dynamic lie, loft and face angle of the golf club head. The golf club head velocity includes path of the golf club head and attack of the golf club head. The golf ball information includes golf ball velocity, golf ball launch angle, golf ball side angle, golf ball speed and golf ball orientation. The golf ball orientation includes the true spin of the golf ball, and the tilt axis of the golf ball which entails the back spin and the side spin of the golf ball. The various measurements will be described in greater detail below.

The system 20 generally includes a computer 22, a camera structure 24 with a first camera unit 26, a second camera unit 28 and an optional trigger device 30, a golf ball 32 and a golf club 33. The system 20 is designed to operate on-course, at a driving range, inside a retail store/showroom, or at similar facilities.

In a preferred embodiment, the camera structure 24 is connected to a frame 34 that has a first platform 36 approximately 46.5 inches from the ground, and a second platform 38 approximately 28.5 inches from the ground. The first camera unit 26 is disposed on the first platform 36 and the second camera unit 28 is disposed on the second platform 38. As shown in FIG. 2, the first platform 36 is at an angle al which is approximately 41.3 degrees relative to a line perpendicular to the straight frame vertical bar of the frame 34, and the second platform 38 is at an angle {acute over (α)}2 which is approximately 25.3 degrees relative to a line perpendicular to the straight frame vertical bar of the frame 34. However, those skilled in the relevant art will recognize that other angles may be utilized for the positioning of the cameras without departing from the scope and spirit of the present invention.

As shown in FIG. 2A, the platforms 36 and 38 are preferably positioned such that the optical axis 66 of the first camera unit 26 does not overlap/intersect the optical axis 68 of the second camera unit 28. The optical view of the first camera unit 26 is preferably bound by lines 62 a and 62 b, while the optical view of the second camera unit 28 is bound by lines 64 a and 64 b. The overlap area defined by curves 70 is the field of view of the system 20.

The first camera unit 26 preferably includes a first camera 40 and optional flash units 42 a and 42 b. The second camera unit 28 preferably includes a second camera 44 and optional flash units 46 a and 46 b. A preferred camera is a complementary metal oxide semiconductor (“CMOS”) camera with active pixel technology and a fall frame rate ranging from 250 to 500 frames per second.

The optional trigger device 30 includes a receiver 48 and a transmitter 50. The transmitter 50 is preferably mounted on the frame 34 a predetermined distance from the camera units 26 and 28. The golf ball is preferably placed on a tee 58. The golf ball 32 is a predetermined length from the frame 34, L1, and this length is preferably 38.5 inches. However, those skilled in the pertinent art will recognize that the length may vary depending on the location and the placement of the first and second camera units 26 and 28. The transmitter 50 is preferably disposed from 10 inches to 14 inches from the cameras 40 and 44.

The data is collected by the cameras and preferably sent to the computer 22 via a cable 52 which is connected to the receiver 48 and the first and second camera units 26 and 28. The computer 22 has a monitor 54 for displaying images generated by the first and second camera units 26 and 28.

The field of view 100 of the cameras 40 and 44 corresponds to the CMOS sensor array 200. In a preferred embodiment, the CMOS sensor array 200 is at least one megapixel in size having one thousand rows of pixels and one thousand columns of pixels for a total of one million pixels. As shown in FIG. 4, a CMOS sensor array 200 preferably has one million active pixels 205. Each active pixel 205 is capable of acting as a single camera to provide an image or a portion of an image. As shown in FIG. 5, the field of view 100 corresponds to the fall frame of the CMOS sensor array 200, which preferably operates at a minimum frame rate ranging from 250 to 500 frames per second, however, it may have a frame rate as low as 30 frames per second. At this frame rate, the CMOS sensor array 200 is monitoring the field of view at a rate of 250-500 times per second and is capable of creating images at 250 to 500 times per second. The CMOS sensor array 200 preferably has one thousand columns of active pixels 205 and one thousand rows of active pixels 205. In a preferred embodiment, the field of view 100 is large enough to capture pre-impact golf club information and post-impact golf ball information. However, those skilled in the pertinent art will recognize that the field of view 100 may be adjusted to focus on any particular action by the golfer such as only pre-impact information, putting information, and the like.

As shown in FIG. 6, an initial region of interest (“ROI”) 210 is established at the edge 150 of the field of view 100 or CMOS sensor array 200. In a preferred embodiment, the initial ROI 210 extends along all of the rows of the sensor array 200 and from 10 to 100 columns of the CMOS sensor array 200 beginning with the first column of active pixels 205 at the edge 150. In establishing an ROI, only those pixels within the ROI are activated while the pixels outside of the ROI are deactivated. Reducing the number of active pixels 205 increases the frame rate in a pseudo-inverse relationship. Thus, if only 25% of the active pixels of the CMOS sensor array are activated, and the full frame rate of the CMOS sensor array 200 is 500 frames per second. Then, the frame rate of the ROI is 2000 frames per second. Thus, reducing the number of active pixels 205 allows for the increased monitoring of a ROI thereby providing increased information about an object entering the ROI since an increased number of images may be obtained of the object within the ROI.

The establishment of an ROI 210 at the edge 150 allows for “through the lens” triggering of the system 20. The through the lens triggering is a substitute for the triggering device 30. The system 20 is monitoring the ROI 210 at a very high frame rate, 1000 to 4000 frames per second, to detect any activity, or the appearance of the golf club 33. The system 20 can be instructed to monitor the ROI 210 for a certain brightness provided by the reflected dots 106 a-c. Once the system 20 detects the object in the ROI 210, the cameras are instructed to gather information on the object. FIG. 7 illustrates the object or golf club, shown as reflective dots 106a-c, as entering the field of view 100.

As the golf club 33 tracks through the field of view 100, the CMOS sensor array 200 creates new ROIs the encompass the reflective dots 106 a-c. As shown in FIG. 8, the golf club 33 (shown by the reflective dots 106 a-c) has moved from its position in FIG. 7. As shown in FIG. 9, a second ROI 215 is established around the golf club 33. It is preferably to create an ROI having a minimum size since the frame rate is increased as the number of active pixels 205 is reduced. Some CMOS cameras only allow reduction in the number of columns which would limit the frame rate.

As the object or golf club 33 moves through the field of view 100, the current ROI preferably overlaps the previous ROI in order to better track the movement of the object or golf club 33. As shown in FIG. 10, the current ROI 220 (shown by bold dashed lines) overlaps the previous ROI 217 (shown by small dashed lines). FIG. 11 illustrates the CMOS sensor array 200 for ROI 220.

FIGS. 12 and 13 illustrate the continued movement of the object or golf club 33 through the field of view 100 and the new ROI 225 encompassing the current position of the golf club 33.

FIG. 14 is a flow chart of a method 300 of using the system 20 of the invention. At box 301, the full CMOS sensor array is active similar to FIG. 4. At box 302, an object such as a golf club 33 is detected within the field of view 100. If analyzing a golfer's swing, this first detection may be the golfer addressing the golf ball 32. During this address of the golf ball, the system 20 may be gathering information concerning the orientation of the club head to the golf ball as the golfer adjusts the position of the golf club to strike the golf ball. The CMOS sensor array 200 is operating at a minimum frame rate since all of the active pixels 205 are activated. However, since the movement of the golf club 33 is slow, this minimum frame rate is sufficient to gather the necessary information.

At box 303, a ROI is created around the object. At box 304, the objected is monitored at a higher frame rate. At box 305, the object is removed from the field of view. If the golf club 33 is monitored during address at box 304, increased information is provided until the golf club is taken away for a swing. Alternatively, if a golf ball 32 is monitored at prior to impact, at impact and post impact, then the ROI is created around the golf ball 32 until it leaves the field of view 100.

FIG. 15 is a flow chart of a specific method 310 for analysis of a golf club at address. At box 311, the CMOS sensor array 200 monitors the field of view 100 at a minimum frame rate. At box 312, the indication markers (reflective dots or other like markers) on the golf club 33 are detected within the field of view 100. At box 313, a ROI is created around the indication markers of the golf club 33. At box 314, the golf club 33 is monitored at a higher frame rate within the ROI. At box 315, the golf club 33 is taken away from the field of view 100.

FIG. 16 is a method 320 for using the system 20 to monitor an object. At box 321, a portion of the field of view 100 is monitored at a maximum rate, similar to the ROI 210 established and monitored in FIG. 6. At box 322, an object is detected within the ROI. At box 323, a first ROI is created around the object. At box 324, a plurality of ROIs are created around the object as it tracks through the field of view 100. At box 325, information is provided on the movement of the object through the field of view.

FIG. 17 is a flow chart of a method 330 for using the system to monitor a golf club. At box 331, a portion of the field of view 100 is monitored at a maximum rate, similar to the ROI 210 established and monitored in FIG. 6. At box 332, a golf club 33, or more specifically the indication markers of the golf club 33, is detected within the ROI. At box 333, a first ROI is created around the indications markers on the golf club 33. At box 334, a plurality of ROIs is created around the indication markers as the golf club tracks through the field of view 100. At box 335, information is provided on the movement of the golf club through the field of view to determine the swing properties of the golfer.

FIG. 18 is a flow chart of a method 340 for using the system to monitor a golf ball during launch. At box 341, an ROI is created around the golf ball prior to impact with a golf club. At box 342, movement of the golf ball 32 is detected by the system 20. At box 343, a plurality of ROIs is created around the golf ball during the initial launch of the golf ball subsequent to impact with a golf club. At box 344, the system analyzes the movement of the golf ball to provide launch parameters of the golf ball 32.

The CMOS sensor array 200 can operate at frames rates 4000 frames per second for a very small ROI. However, processing time between images or frames requires preferably less than 500 microseconds, and preferably less than 250 microseconds. The processing time is needed to analyze the image to determine if an object is detected and if the object is moving.

The system 20 may be calibrated using many techniques known to those skilled in the pertinent art. One such technique is disclosed in U.S. Pat. No. 5,803,823, which is hereby incorporated by reference. The system 20 is calibrated when first activated, and then may operate to analyze golf swings for golfers until deactivated.

As mentioned above, the system 20 captures and analyzes golf club information and golf ball information during and after a golfer's swing. The system 20 uses the images and other information to generate the information on the golfer's swing. The golf club 33 has at least two, but preferably three highly reflective points 106 a-c preferably positioned on the shaft, heel and toe of the golf club 33. The highly reflective points 106 a-c may be inherent with the golf club design, or each may be composed of a highly reflective material that is adhesively attached to the desired positions of the golf club 33. The points 106 a-c are preferably highly reflective since the cameras 40 and 44 are preferably programmed to search for two or three points that have a certain brightness such as 200 out of a gray scale of 0-255. The cameras 40 and 44 search for point pairs that have approximately one inch separation, and in this manner, the detection of the golf club 33 is acquired by the cameras for data acquisition.

As shown in FIG. 19, the first row of acquired highly reflective points 106 a (on the shaft) is designated series one, the second row of acquired highly reflective points 106 b (on the heel) is designated series two, and the third row of acquired highly reflective points 106 c (on the toe) is designated series three. The first row is the acquired highly reflective points 106 a from the shaft, the second row is the acquired highly reflective points 106 a from the heel, and the third row is the acquired highly reflective points 106 a from the toe. The following equation is used to acquire the positioning information:


d=[(Ptx−Pnx)2+(Pty−Ptny)2 . . . ]1/2

where d is the distance, Ptx is the position in the x direction and Pty is the position in the y direction.

The system 20 may use a three point mode or a two point mode to generate further information. The two point mode uses Vtoe, Vheel and Vclubtop to calculate the head speed.


V toe=[(Ptx 3−Ptx 1)2+(Pty 3−Pty 1)2+(Ptz 3−Ptz 1)2]1/2[1/δT]


V heel=[(Ptx 3−Ptx 1)2+(Pty 3−Pty 1)2+(Ptz 3−Ptz)2]1/2[1/δ]


V clubtop=[Vtoe+Vheel][½]


Vy=[(y 3heel −y 1heel)2+(y 3toe 1toe)2]1/2[1/(2*δT)]


Vz=[(z 3heel −Z 1heel)2+(z 3toe −z 1toe)2]1/2[1/(2*δT)]

This information is then used to acquire the path angle and attack angle of the golf club 33. The Path angle=sin−1(Vy/[V]) where [V] is the magnitude of V.

The attack angle=sin−1(Vz/[V]), and the dynamic loft and dynamic lie are obtained by using Series one and Series two to project the loft and lie onto the vertical and horizontal planes.

The two point mode uses the shaft highly reflective point 106 a or the toe highly reflective point 106 c along with the heel highly reflective point 106 b to calculate the head speed of the golf club, the path angle and the attack angle. Using the shaft highly reflective point 106 a, the equations are:


V heel[(Ptx 3−Ptx 1)2+(Pty 3−Pty 1)2+(Ptz 3−Ptz 1)2]1/2[1/δ]


V shaft[(Ptx 3−Ptx 1)2+(Pty 3−Pty 1)2+(Ptz 3−Ptz 1)2]1/2[1/δT]


V center=1.02*(Vshaft +V heel)


Vy=[(y 3heel −y 1heel)2+(y 3shaft −y 1shaft)2]1/2[1/(2*δT)]


Vz=[(z 3heel −Z 1heel)2+(z 3shaft −Z 1shaft)2]1/2[1/(2*δT)]

The Path angle=sin−1(Vy/[V]) where [V] is the magnitude of V.

The attack angle=sin−1 (Vz/[V]).

Using the toe highly reflective point 106 c, the equations are:


V toe=[(x 3 −x 1)2+(y 3 −y 1)2+(z 3 −z 1)2]1/2[1/δT]


V heel=[(x 2 −x 1)2+(y 2 −y 1)2+(z 2 −z 1)2]1/2[1/δT]


V clubtop =[V toe +V heel][1/2]

The path angle=sin−1(VyClubtop/[Vclubtop]) where [Vclubtop] is the magnitude of Vclubtop.

The attack angle=sin−1(Vzclubtop/[Vclubtop]) where [Vclubtop] is the magnitude of Vclubtop.

The golf ball information is mostly obtained from images of the golf ball post impact. First, the best radius and position of the two dimensional areas of interest are determined from the images. Next, all of the combinations of the golf ball 32 centers in the images are matched and passed through a calibration model to obtain the X, Y, and Z coordinates of the golf ball 32. The system 20 removes the pairs with an error value greater then 5 millimeters to get acceptable X, Y, Z coordinates. Next, the strobe times from the flash units 42 a-b and 46 a-b are matched to the position of the golf ball 32 based on the estimated distance traveled from the images. Next, the velocity of the golf ball 32 is obtained from Vx, Vy and Vz using a linear approximation. Next the golf ball speed is obtained by calculating the magnitude of Vx, Vy and Vz.

The launch angle=sin−1 (Vz/golf ball speed),

and the spin angle=sin−1 (Vy/golf ball speed).

Next, the system 20 looks for the stripes 108 a-b, as shown in FIGS. 20 and 20A, on the golf ball 32 by using a random transformation searching for the spot of greatest contrast. X, Y and Z coordinates are used with the arc of stripe 108 a and the arc of stripe 108 b to orient the arc on the golf ball. Then, the system 20 determines which arc is most normal using (X2+y2)1/2.

Next, the θ angle of the golf ball 32 is measured by taking the first vector and the second vector and using the equation:


θ=cos−1[(vector A1)(vector A2)]/([V1][V2])

where [V1] is the magnitude of V1 and [V2] is the magnitude of V2.

As the golf ball 32 rotates from the position shown in FIG. 20 to the position shown in FIG. 20A, the angle θ is determined from the position of vector A at both rotation positions. This allows for the spin to be determined. The back spin is calculated and applied to the first set of axis with a tilt axis of zero. The resultant vectors are compared to those of the next image and a theta is calculated for each of the vectors. This is done for each tilt axis until the Theta between the rotated first set of axis and the second set of axis is minimized.

The following is an example of how the system captures and analyzes golf club information and golf ball information during and after a golfer's swing. The golf club information includes golf club head orientation, golf club head velocity, and golf club spin. The golf club head orientation includes dynamic lie, loft and face angle of the golf club head. The golf club head velocity includes path of the golf club head, attack of the golf club head and downrange information. The golf ball information includes golf ball velocity, golf ball launch angle, golf ball side angle, golf ball speed manipulation and golf ball orientation. The golf ball orientation includes the true spin of the golf ball, and the tilt axis of the golf ball which entails the back spin and the side spin of the golf ball.

The system 20 pairs the points 106 a-c, verifying size, separation, orientation and attack angle. Then, the system 20 captures a set of six points (three pairs) from a first find as shown in FIGS. 21 and 21A. Then, the system 20 searches above and below the three pairs for a second find, as shown in FIG. 22 and 23. The repeated points 106 are eliminated and the results are displayed from the find, as shown in FIGS. 24 and 25. The points of the final pairs are processed by the computer 22 and displayed as shown in FIG. 26.

Next the speed of the head of the golf club 33 is determined by the system 20 using the equations discussed above.

Next the path angle and the attack angle of the golf club 33 is determined by the system 20. Using the methods previously described, the attack angle is determined from the following equation:

Attack angle=−a tan (δz/δx)

Where δz is the z value of the midpoint between 106 a 1 and 106 b 1 minus the z value of the midpoint between 106 a 3 and 106 b 3. Where δx is the x value of the midpoint between 106 a 1 and 106 b 1 minus the x value of the midpoint between 106 a 3 and 106 b 3.

The path angle is determined from the following equation:

path angle=−a tan (δy/δx)

Where δy is the y value of the midpoint between 106 a 1 , and 106 b 1 minus the y value of the midpoint between 106 a 3 and 106 b 3. Where δx is the x value of the midpoint between 106 a 1 and 106 b 1 minus the x value of the midpoint between 106 a 3 and 106 b 3.

Next, the golf ball 32 data is determined by the system 20. First, the thresholding of the image is established as shown in FIG. 27, at a lower gray scale value, approximately 100 to 120, to detect the golf ball 32. The golf ball 32 is shown at a first position 103, a second position 104 a, a third position 104 b, a fourth position 104 c and a fifth position 104 d. Next, well-known edge detection methods are used to obtain the best golf ball 32 center and radius, as shown in FIG. 28. Next, the stereo correlation of two dimensional points on the golf ball 32 is performed by the system 20 as in FIG. 29, which illustrates the images of the first camera 40 and the second camera 44.

Next, as shown in FIG. 30, with the positioning information provided therein, the speed of the golf ball 32, the launch angle of the golf ball 32, and the side angle of the golf ball 32 is determined by the system 20. The speed of the golf ball is determined by the following equation:

Golf ball speed=[δX2+δY2+δZ2]1/2/δT. For the information provided in FIG. 30, the speed of the golf ball=[(−161.68+(−605.26))2+(−43.41+(−38.46))2+(−282.74+(−193.85))2]1/2/(13127−5115), which is equal to 126 MPH once converted from millimeters over microseconds.

The launch angle of the golf ball 32 is determined by the following equation:

Launch angle=sin−1(Vz/ golf ball speed) where Vz=δ/δT. For the information provided in FIG. 30, Vz=[(−282.74+(−193.85)]/(13127−5115)=11.3 MPH. Then, the launch angle=sin−1(1.4/126.3)=11.3 degrees.

The side angle of the golf ball 32 is determined by the following equation: Side angle=sin−1(Vy/golf ball speed) where Vy=δY/δT. For the information provided in FIG. 30, Vy=[(−43.41+(−38.46)]/(13127−5115)=1.4 MPH. Then, the side angle=sin−1(1.4/126.3)=0.6 degrees.

The ball spin is calculated by determining the location of the three striped on each of the acquired golf balls. Matching each axis in the field of view and determine which of the axis is orthogonal to the vertical plane. The spin is then calculated by:


θ=a cos ((vectorA1 dot vector A2)/mag(v1)*mag(v2)) as discussed above.

From the foregoing it is believed that those skilled in the pertinent art will recognize the meritorious advancement of this invention and will readily understand that while the present invention has been described in association with a preferred embodiment thereof, and other embodiments illustrated in the accompanying drawings, numerous changes, modifications and substitutions of equivalents may be made therein without departing from the spirit and scope of this invention which is intended to be unlimited by the foregoing except as may appear in the following appended claims. Therefore, the embodiments of the invention in which an exclusive property or privilege is claimed are defined in the following appended claims.

Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US7641565 *Dec 14, 2006Jan 5, 2010Wintriss Engineering CorporationMethod and apparatus for detecting the placement of a golf ball for a launch monitor
US8047050 *Apr 6, 2009Nov 1, 2011National Pingtung University Of Science And TechnologyPerformance test apparatus and image taking device thereof
US8734264 *Jun 27, 2012May 27, 2014Bridgestone CorporationSystem and method for measurement and analysis of behavior of golf club head in golf swing
US20090325721 *Jun 25, 2009Dec 31, 2009Gbt Technologies, LlcSystems and methods for golf ball selection
US20130005495 *Jun 27, 2012Jan 3, 2013Bridgestone Sports Co., Ltd.System and method for measurement and analysis of behavior of golf club head in golf swing
Classifications
U.S. Classification473/199, 473/223, 473/233, 473/407, 473/409
International ClassificationA63B69/36
Cooperative ClassificationA63B69/3614, A63B24/0006, A63B24/0003, A63B2024/0056, A63B2220/05, A63B69/3658, A63B2024/0037, A63B2024/0031, A63B2220/30, A63B69/3623, A63B24/0021, A63B2220/806, A63B2024/0028, A63B2220/35
European ClassificationA63B69/36D, A63B69/36E, A63B24/00A1, A63B24/00E, A63B24/00A
Legal Events
DateCodeEventDescription
Aug 20, 2007ASAssignment
Owner name: CALLAWAY GOLF COMPANY, CALIFORNIA
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:MANWARING, SCOTT R.;REEL/FRAME:019717/0037
Effective date: 20040507