A method and system create a geometric object model for use in machine vision inspection. A pixel image representation of an object is acquired. Based on this pixel image representation, part models for the parts of the object are generated. Each part model corresponds to a different part of the object. From the part models of the object, a model for the entire object can be created. Using this created object model, a test inspection is performed on a set of test images, and each of the test images is associated with a set of known inspection measurements. The test inspection produces a set of testing inspection measurements. If the test inspection yields satisfactory performance, the object models created are stored. |
Citations|
| US4980971 | Dec 14, 1989 | Jan 1, 1991 | AT&T Bell Laboratories | Method and apparatus for chip placement | | US5060276 | May 31, 1989 | Oct 22, 1991 | AT&T Bell Laboratories | Technique for object orientation detection using a feed-forward neural network | | US5113565 | Jul 6, 1990 | May 19, 1992 | International Business Machines Corp. | Apparatus and method for inspection and alignment of semiconductor chips and conductive lead frames | | US5226095 | May 26, 1992 | Jul 6, 1993 | Matsushita Electric Industrial Co., Ltd. | Method of detecting the position of an object pattern in an image | | US5268999 | Mar 20, 1992 | Dec 7, 1993 | Ricoh Company, Ltd. | Modeling method and system using solid data having functional structure and normal projection drawing dimensional format | | US5343028 | Aug 10, 1992 | Aug 30, 1994 | United Parcel Service of America, Inc. | Method and apparatus for detecting and decoding bar code symbols using two-dimensional digital pixel images | | US5371690 | Jan 17, 1992 | Dec 6, 1994 | Cognex Corporation | Method and apparatus for inspection of surface mounted devices | | US5471541 | Nov 16, 1993 | Nov 28, 1995 | National Research Council of Canada | System for determining the pose of an object which utilizes range profiles and synethic profiles derived from a model | | US5495537 | Jun 1, 1994 | Feb 27, 1996 | Cognex Corporation | Methods and apparatus for machine vision template matching of images predominantly having generally diagonal and elongate features | | US5497451 | Jan 22, 1992 | Mar 5, 1996 | | Computerized method for decomposing a geometric model of surface or volume into finite elements | | US5500906 | Jan 14, 1994 | Mar 19, 1996 | Cognex Corporation | Locating curvilinear objects using feathered fiducials | | US5545887 | Oct 25, 1994 | Aug 13, 1996 | United Parcel Service of America, Inc. | Method and apparatus for decoding bar code symbols using subpixel scan lines | | US5602937 | Jun 1, 1994 | Feb 11, 1997 | Cognex Corporation | Methods and apparatus for machine vision high accuracy searching | | US5621807 | Oct 13, 1994 | Apr 15, 1997 | Dornier GmbH | Intelligent range image camera for object measurement | | US5625715 | Oct 21, 1993 | Apr 29, 1997 | U.S. Philips Corporation | Method and apparatus for encoding pictures including a moving object | | US5627912 | Dec 6, 1995 | May 6, 1997 | Yozan Inc. | Inspection method of inclination of an IC | | US5627915 | Jan 31, 1995 | May 6, 1997 | Princeton Video Image, Inc. | Pattern recognition system employing unlike templates to detect objects having distinctive features in a video field | | US5663809 | May 16, 1995 | Sep 2, 1997 | Sharp Kabushiki Kaisha | Image processing apparatus | | US5828769 | Oct 23, 1996 | Oct 27, 1998 | Autodesk, Inc. | Method and apparatus for recognition of objects via position and orientation consensus of local image encoding | | US5850469 | Nov 4, 1996 | Dec 15, 1998 | General Electric Company | Real time tracking of camera pose | | US5974169 | Mar 20, 1997 | Oct 26, 1999 | Cognex Corporation | Machine vision methods for determining characteristics of an object using boundary points and bounding regions | | US6084592 | Jun 18, 1998 | Jul 4, 2000 | Microsoft Corporation | Interactive construction of 3D models from panoramic images |
Referenced by|
| US7171036 | Mar 14, 2003 | Jan 30, 2007 | Cognex Technology and Investment Corporation | Method and apparatus for automatic measurement of pad geometry and inspection thereof | | US7272254 | Jul 9, 2003 | Sep 18, 2007 | General Electric Company | System and method for analyzing and identifying flaws in a manufactured part | | US7463763 | Apr 5, 2005 | Dec 9, 2008 | Dainippon Screen Mfg. Co., Ltd. | Apparatus, method, and program for assisting in selection of pattern element for pattern matching | | US7684625 | Nov 12, 2003 | Mar 23, 2010 | Fuji Xerox Co., Ltd. | Image processing apparatus, image processing method, image processing program, printed matter inspection apparatus, printed matter inspection method and printed matter inspection program |
Claims1. A method for creating a two-dimensional geometric object model describing the geometry of an object for use in machine vision inspection, said method comprising: - acquiring a pixel image representation of an object;
- generating a set of two-dimensional geometric part models of said object based on said pixel image representation, said two-dimensional geometric part models corresponding to different respective parts of said object, said two-dimensional geometric object model comprising said set of two-dimensional geometric part models;
- obtaining a test image containing the visual appearance of said object and a given known inspection measurement associated with the test image;
- performing test inspection on said test image using said two-dimensional geometric object model to produce a testing inspection measurement; and
- retaining said two-dimensional geometric object model when said given testing inspection measurement deviates from said given known inspection measurement by an amount lower than a predetermined threshold.
2. The method of claim 1, further comprising: - calibrating an image acquisition system to enable said acquiring to obtain calibrated said pixel image representation of said object; and
- specifying one or more constraints for said two-dimensional geometric object prior to said generating to provide additional information constraining said generating.
3. The method of claim 2, wherein said constraints include the geometric shape of said object. 4. The method of claim 2, wherein said constraints include the spatial relationship among different parts of said object. 5. The method of claim 1, said generating further comprising: - determining the dimension of said part of said object; and determining the position of said part of said object.
6. The method of claim 1, wherein said two-dimensional geometric object model includes geometric descriptions expressed with respect to a coordinate system. 7. The method of claim 1, said generating further comprising: - determining a coordinate system with respect to a specified reference; and
- generating said two-dimensional geometric object model with respect to said coordinate system.
8. The method of claim 1, further comprising: - refining one or more of said two-dimensional geometric part models;
- configuring a machine vision inspection tool based on said two-dimensional geometric object model;
- evaluating the performance of said two-dimensional geometric object model by evaluating testing inspection measurements in relation to known inspection measurements to produce an indication that said two-dimensional geometric object model is one of satisfactory and unsatisfactory;
- determining when said evaluating produces an indication of unsatisfactory, one or more causes that caused the unsatisfactory indication; and
- deciding an act to which to return for an iteration based on said cause, said act including said generating, said creating, said refining, and said configuring.
9. A system for creating a two-dimensional geometric object model describing the geometry of an object for use in machine vision inspection, said system comprising: - an image acquisition system to acquire a pixel image representation of an object;
- a generator to generate two-dimensional geometric part models of said object based on said pixel image representation, said two-dimensional geometric part models corresponding to different respective parts of said object, a said two-dimensional geometric object model comprising said part models;
- an image storage mechanism to store a test image and a given known inspection measurement associated with said test image;
- a testing unit to perform machine vision inspection on said test image using said two-dimensional geometric object model to produce a testing inspection measurement; and
- an object model storage mechanism to retain said two-dimensional geometric object model when said testing inspection measurement deviates from said given known inspection measurement by an amount lower than a predetermined threshold.
10. The system of claim 9, further comprising: - a calibration unit to calibrate an image acquisition system to enable said calibration unit to obtain calibrated said pixel image representation of said object; and
- a constraint set up unit to specify one or more constraints for said object to provide additional information constraining said generator.
11. The system of claim 10, wherein said constraints include the geometric shape of said object. 12. The system of claim 10, wherein said constraints include the spatial relationship among different parts of said object. 13. The system of claim 9, said generator further comprising: - a first determiner to determine the dimension of said part of said object; and
- a second determiner to determine the position of said part of said object.
14. The system of claim 9, wherein said two-dimensional geometric object model includes geometric descriptions expressed with respect to a coordinate system. 15. The system of claim 9, said generator further comprising: - a determiner to determine a coordinate system with respect to a specified reference; and
- a generator to generate said two-dimensional geometric object model with respect to said coordinate system.
16. The system of claim 9, further comprising: - a refiner to refine one or more of said two-dimensional geometric part models;
- a configuration unit that configures a machine vision inspection tool based on said two-dimensional geometric object model; and
- an evaluation unit to evaluate the performance of said two-dimensional geometric object model by evaluating testing inspection measurement in relation to known inspection measurement to produce an indication that said two-dimensional geometric object model is one of satisfactory and unsatisfactory;
- a determiner to determine when said evaluation unit yields an indication of unsatisfactory, one or more causes that caused the unsatisfactory indication; and
- a decider to decide an act to which to return for an iteration based on said cause, said act including steps performed by said generator, by said creator, by said refiner, and by said configuration unit.
17. A medium having information recorded thereon, such that when said information is read and executed by a computer, the computer is caused to: - acquire a pixel image representation of an object;
- generate two-dimensional geometric part models of an object based on said pixel image representation, said two-dimensional geometric part models corresponding to different respective parts of said object, said two-dimensional geometric object model comprising said two-dimensional geometric part models;
- obtain a test image, containing the visual appearance of said object, and a given known inspection measurement associated with said test image;
- perform test inspection on said test image using said two-dimensional geometric object model to produce a testing inspection measurement; and
- retain said two-dimensional geometric object model when said test inspection measurement deviates from said given known inspection measurement by an amount lower than a predetermined threshold.
18. The medium of claim 17, said information recorded on said medium further causes said computer to: - calibrate an image acquisition system to enable said acquiring to obtain calibrated said pixel image representation of said object; and
- specify one or more constraints for said object prior to said generating to provide additional information constraining said generating.
19. The medium of claim 18, wherein said constraints include the geometric shape of said object. 20. The medium of claim 18, wherein said constraints include the spatial relationship among different parts of said object. 21. The medium of claim 17, wherein said information recorded on said medium further causes said computer to: - determine the dimension of said part of said object; and
- determine the position of said part of said object.
22. The medium of claim 17, wherein said two-dimensional geometric object model includes geometric descriptions expressed with respect to a coordinate system. 23. The medium of claim 17, wherein said information recorded on said medium further causes said computer to: - determine a coordinate system with respect to a specified reference; and generate said two-dimensional geometric object model with respect to said coordinate system.
24. The medium of claim 17, said information recorded on said medium further causes said computer to: - refine one or more of said two-dimensional geometric part models;
- configure a machine vision inspection tool based on said two-dimensional geometric object model;
- evaluate the performance of said two-dimensional geometric object model by evaluating testing inspection measurement in relation to known inspection measurement to produce an indication that said object model is one of satisfactory and unsatisfactory;
- determine when said evaluating produces an indication of unsatisfactory, one or more causes that caused the unsatisfactory indication; and
- decide an act to which to return for an iteration based on said cause, said act including said generating, said creating, said refining, and said configuring.
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