Transprojection of geometry data

• US 20050151963A1
• Filed: 01/14/2004
• Published: 07/14/2005
• Est. Priority Date: 01/14/2004
• Status: Active Grant

• Current Assignee: Hexagon Metrology Incorporated (Hexagon AB)
• Original Assignee: Hexagon Metrology Incorporated (Hexagon AB)
• Inventors: Eaton, Homer, Pulla, Sandeep
• Granted Patent: US 7,693,325 B2
• Time in Patent Office: Days
• US Class Current: 356/139.30
• CPC Class Codes: G01B 21/02 for measuring length, width, or thickness G01B21/10 takes precedence
• CPC Class Codes: G01B 21/04 by measuring coordinates of points
• CPC Class Codes: G01B 9/02023 Indirect probing of object, e.g. via influence on cavity or fibre
• CPC Class Codes: G01B 9/02029 Combination with non-interferometric systems, i.e. for measuring the object
• CPC Class Codes: G01B 9/0203 With imaging systems
• CPC Class Codes: G01B 9/02031 With non-optical systems, e.g. tactile
• CPC Class Codes: G01B 9/0205 of probe head
• CPC Class Codes: G06T 11/60 Editing figures and text; Combining figures or text
• CPC Class Codes: G06T 2207/20221 Image fusion; Image merging
• CPC Class Codes: G06T 7/73 using feature-based methods

Abstract

A system and methods for transprojection of geometry data acquired by a coordinate measuring machine (CMM). The CMM acquires geometry data corresponding to 3D coordinate measurements collected by a measuring probe that are transformed into scaled 2D data that is transprojected upon various digital object image views captured by a camera. The transprojection process can utilize stored image and coordinate information or perform live transprojection viewing capabilities in both still image and video modes.

Claims

1. A system for coordinate visualization, the system comprising:

a measuring system for acquiring three dimensional coordinate data from a target location on an object;

an imaging member that generates an image of at least a portion of said object from a vantage point whose three dimensional location is known; and

a processor which receives said three dimensional coordinate data, said image and said three dimensional location, said processor producing image data overlaying a visible marker at said target location on said image.

2. The system for coordinate visualization of claim 1, wherein the measuring system comprises a coordinate acquisition member configured to acquire said three dimensional coordinate data from said target location on said object.

3. The system for coordinate visualization of claim 2, wherein said coordinate acquisition member is secured to an articulated arm member moveable about a plurality of axes and capable of positioning said coordinate acquisition member in a plurality of orientations about the object.

4. The system for coordinate visualization of claim 3, wherein said imaging member is secured to said articulated arm member so as to be cooperatively positioned in conjunction with said coordinate acquisition member to acquire said image from a selected perspective about said object.

5. The system of claim 2 wherein, said coordinate acquisition member comprises a probe selected from the group consisting of:

a contact-sensitive probe, a remote-scanning probe, a laser-scanning probe, a probe that uses a strain gauge for contact detection, a probe that uses a pressure sensor for contact detection, a probe that used an infrared beam for positioning, and a probe configured to be electrostatically-responsive.

6. The system for coordinate visualization of claim 1, wherein said visible marker comprises coordinate information scaled and overlaid at said target location on said image.

7. The system for coordinate visualization of claim 1, wherein the processor overlays said visible marker on said image to reflect the position and orientation of said visible marker at said target location in the context of the image perspective.

8. The system for coordinate visualization of claim 1 wherein, the processor translates the three dimensional location of said imaging member into three dimensional coordinates associated with a coordinate system for said object.

9. The system for coordinate visualization of claim 8 wherein, the processor utilizes at least one modeling parameter to relate the three dimensional location of said imaging member to the three dimensional coordinates associated with the coordinate system for said object.

10. The system for coordinate visualization of claim 9 wherein, the at least one modeling parameter is derived in part from focal characteristics of the imaging member.

11. The system for coordinate visualization of claim 10 wherein, the focal characteristics used to derive the at least one modeling parameter are selected from the group consisting of:

imaging member angle, imaging member focal length, imaging member distortion characteristics, imaging member offset characteristics, imaging member scaling characteristics, imaging member orientation, and imaging member position.

12. The system for coordinate visualization of claim 1 wherein, the processor overlays the visible marker at said target location on said image by identifying a virtual coordinate system associated with the at least one image that is a scaled representation of a physical coordinate system associated with the target location on said object such that the coordinate data obtained from the target location on said object is modeled in the virtual coordinate system.

13. The system for coordinate visualization of claim 1 wherein, the object is at least partially contained in a target area comprising at least one target having a known positional relationship to the target area, the target further used to calibrate the image of the target area.

14. The system for coordinate visualization of claim 13 wherein, calibration of the image of the target area further comprises:

acquiring three dimensional coordinate information for the target; and

relating the three dimensional coordinate information for the target to a target representation in the image wherein the relationship is reflected by a calibration parameter.

15. The system for coordinate visualization of claim 14 wherein, the calibration parameter is applied to said coordinate data from said target location on said object to accurately overlay the visible marker at said target location on said image.

16. The system for coordinate visualization of claim 14 wherein, the calibration parameter is determined using a target detection functionality in which the processor discerns a representation of the target within the image and associates the target coordinate information with the representation of the target.

17. The system for coordinate visualization of claim 16 wherein, the target detection functionality discerns the target on the basis of at least one target characteristic selected from the group consisting of:

shape, size, coloration, location, luminosity, brightness, and contrast.

18. The system for coordinate visualization of claim 17 wherein, the at least one target characteristic is evaluated for at least one selected seed pixel of the image and a search is performed to identify other pixels associated with the target.

19. The system for coordinate visualization of claim 18 wherein, the pixel identification search comprises a recursive search performed in the vicinity of the selected seed pixel.

20. The system for coordinate visualization of claim 1 wherein, the image is two dimensional in nature and the processor transforms the three dimensional coordinate data into a representative two dimensional form such that when the two dimensional form of the coordinate data is overlaid upon the image, the visible marker accurately reflects the position of the target location in the context of the image.

21. The system for coordinate visualization of claim 20 wherein, the coordinate data transformation is accomplished using at least one imaging member modeling parameter.

22. The system for coordinate visualization of claim 1 wherein, a plurality of images are acquired from various perspectives and the processor displays selected images with the overlaid visible marker on the basis of the measuring system location with respect to the object.

23. The system for coordinate visualization of claim 22 wherein, the processor selects the image and visible marker to display by identifying the image closest in perspective to the vantage point of the measuring system position.

24. The system for coordinate visualization of claim 23 wherein, the position of the imaging device relative to the measuring system is interpolated or extrapolated from the associated coordinate data.

25. The system for coordinate visualization of claim 1 wherein, the processor selects an appropriate image and corresponding visible marker to display on the basis of a coordinate range associated with each image such that when the measuring system is positioned substantially within the coordinate range, the processor displays that image and corresponding visible marker at said target location on said image.

26. The system for coordinate visualization of claim 1 wherein, the processor displays the image and corresponding visible marker at said target location on said image based upon at least one image characteristic.

27. The system for coordinate visualization of claim 26 wherein, the at least one image characteristic is selected from the group consisting of:

magnification, perspective, orientation, and view.

28. The system for coordinate visualization of claim 1 wherein, the processor performs an adjustment operation to the image and corresponding visible marker at said target location on said image to achieve a selected view of the image.

29. The system for coordinate visualization of claim 28 wherein, the adjustment operation is selected from the group of operations consisting of:

realignment, rotation, skewing, cropping, and zooming.

30. The system for coordinate visualization of claim 1 wherein, the processor displays the image and visible marker in a live operational mode that is responsive to the position of measuring system as it is moved about the object.

31. The system for coordinate visualization of claim 1 wherein, the imaging member comprises a camera capable of generating still images or video images.

32. The system for coordinate visualization of claim 1 wherein, the imaging member comprises an imaging device selected from the group consisting of:

X-ray imaging devices, ultrasonic imaging devices, laser imaging devices, infrared imaging devices, optical imaging devices, and digital imaging devices.

33. The system for coordinate visualization of claim 1 wherein, the image is three dimensional in form.

34. A method for displaying geometry and imaging information, the method comprising:

acquiring at least one image of at least a portion of a target area;

mapping points of the image to corresponding points in the target area;

acquiring geometry information for an object in the target area;

performing a transformation operation to map the geometry information of the object to the image; and

displaying the image overlaid with the geometry information.

35. The method for displaying geometry and imaging information of claim 34, further comprising:

associating an image coordinate system with the image and a target coordinate system with the target area;

identifying at least one calibration parameter that relates the image coordinate system to the target coordinate system; and

applying the at least one calibration parameter to the geometry information of the object to transform the geometry information such that the image is overlaid with the geometry information accurately reflecting the position and characteristics of geometry information in the context of the image.

36. The method for displaying geometry and imaging information of claim 35 wherein, the image coordinate system is two dimensional and the target coordinate system is three dimensional and the at least one calibration parameter relates three dimensional points of the target coordinate system to two dimensional points of the image coordinate system.

37. The method for displaying geometry and imaging information of claim 36 wherein, the geometry information is three dimensional and the image is two dimensional and the transformation operation maps the three dimensional geometry information to the two dimensional image.

38. The method for displaying geometry and imaging information of claim 35 wherein, the image coordinate system is three dimensional and the target coordinate system is three dimensional and the at least one calibration parameter relates three dimensional points of the target coordinate system to three dimensional points of the image coordinate system.

39. The method for displaying geometry and imaging information of claim 38 wherein, the geometry information is three dimensional and the image is three dimensional and the transformation operation maps the three dimensional geometry information to the three dimensional image.

40. The method for displaying geometry and imaging information of claim 35 wherein, the calibration parameter is identified by:

designating at least one calibration target having a known positional relationship to the target area;

acquiring at least one image containing a representation of the at least one calibration target;

applying a target detection operation to discern the representation of the at least one calibration target within the image;

associating the target'"'"'s known positional relationship to the target area with the target coordinate system;

associating the representation of the at least one calibration target with the image coordinate system; and

developing the calibration parameter to relate the target coordinate system and image coordinate system on the basis of the target and its representation in the two coordinate systems.

41. The method for displaying geometry and imaging information of claim 40 wherein, the target detection functionality discerns the representation of the at least one calibration target based on at least one target characteristic selected from the group consisting of:

shape, size, coloration, location, luminosity, brightness, and contrast.

42. The method for displaying geometry and imaging information of claim 41 wherein, the at least one target characteristic is evaluated for at least one selected seed pixel of the image and a search is performed to identify other pixels associated with the calibration target.

43. The method for displaying geometry and imaging information of claim 42 wherein, the pixel identification search comprises a recursive search performed in the vicinity of the at least one selected seed pixel.

44. The method for displaying geometry and imaging information of claim 34 wherein, the geometry information relates to an object at least partially contained within the target area and the image contains a representation of at least a portion of the object which are displayed to accurately reflect scaled coordinate details of the object in the perspective of the image.

45. The method for displaying geometry and imaging information of claim 34 wherein, the geometry information is acquired using a probe affixed to an articulated measuring arm capable of being positioned about the target area.

46. The method for displaying geometry and imaging information of claim 45 wherein, the probe comprises a coordinate acquisition device selected from the group consisting of:

a contact-sensitive probe, a remote-scanning probe, a laser- scanning probe, a probe that uses a strain gauge for contact detection, a probe that uses a pressure sensor for contact detection, a probe that used an infrared beam for positioning, and a probe configured to be electrostatically-responsive.

47. The method for displaying geometry and imaging information of claim 45 wherein, a plurality of images are acquired from various perspectives and selected images and geometry information are displayed on the basis of the probe location about the target area.

48. The method for displaying geometry and imaging information of claim 47 wherein, the image and geometry information to be displayed are determined by identifying the image closest in perspective to the target area view from the current probe position.

49. The method for displaying geometry and imaging information of claim 48 wherein, each image is associated with geometry information characterizing the perspective from which the image was acquired.

50. The method for displaying geometry and imaging information of claim 49 wherein, images and geometry information to be displayed are identified on the basis of a coordinate range associated with each image such that when the probe is positioned substantially within the coordinate range, the image for the coordinate range and corresponding geometry information are displayed.

51. The method for displaying geometry and imaging information of claim 34 wherein, the image and geometry information are displayed based upon at least one image characteristic.

52. The method for displaying geometry and imaging information of claim 51 wherein, the at least one image characteristic is selected from the group consisting of:

magnification, perspective, orientation, and view.

53. The method for displaying geometry and imaging information of claim 34 wherein, a processing operation is performed to the image and corresponding geometry information to achieve a selected perspective or view of the image.

54. The method for displaying geometry and imaging information of claim 53 wherein, the processing operation is selected from the group consisting of:

realignment, rotation, skew, cropping, and zooming.

55. The method for displaying geometry and imaging information of claim 34 wherein, the image is acquired using an imaging member comprising a camera capable of generating still images or video images.

56. The method for displaying geometry and imaging information of claim 34 wherein, the image is acquired using an imaging device selected from the group consisting of:

X-ray imaging devices, ultrasonic imaging devices, laser imaging devices, infrared imaging devices, optical imaging devices, and digital imaging devices.

57. A system for coordinate acquisition and visualization, the system comprising:

an arm member having a probe member attached thereto, the arm member positioned with respect to a target area such that the probe member acquires coordinate information from the target area;

an imaging member configured to generate at least one image of at least a portion of the target area; and

a controller configured to receive the coordinate information and the at least one image whereupon the controller adjusts and overlays the coordinate information upon the at least one image to reflect the position and orientation of the coordinate information in the context of the image.

58. The system for coordinate acquisition and visualization of claim 57 wherein, the arm member moveably positions the probe member about the target area.

59. The system for coordinate acquisition and visualization of claim 58 wherein, the arm member is articulated and moveable about at least one axis to position the probe member in a plurality of orientations with respect to the target area.