Electro-optical sensors with fiber optic bundles

• US 4,515,479 A
• Filed: 03/22/1983
• Issued: 05/07/1985
• Est. Priority Date: 07/29/1980
• Status: Expired due to Term

• Current Assignee: LMI Technologies Inc.
• Original Assignee: Diffracto, Ltd. (LMI Technologies Inc.)
• Inventors: Pryor, Timothy R.
• Primary Examiner(s): Rosenberger, R. A.
• Application Number:
  US06/477,775
• Time in Patent Office: 777 Days
• Field of Search: 356/384, 356/375, 250/227, 250/578, 350/96.24
• US Class Current: 356/615
• CPC Class Codes: G01B 11/00 Measuring arrangements characterised by the use of optical techniques
• CPC Class Codes: G01B 11/024 by means of diode-array scanning
• CPC Class Codes: G01D 5/268 using optical fibres G01D5/28 - G01D5/38 take precedence
• CPC Class Codes: Y10S 250/901 with gap between light guide elements, includes open light path preset

Abstract

A method and apparatus for determining the dimension, location, orientation, presence, or identity of at least a portion of an object. An object or a portion thereof is imaged onto an end of an at least partially non-coherent optical fiber bundle whereby the image incident on said end of said fiber bundle is transmitted to the other end thereof. The image is transferred from the other end of the non-coherent optical fiber bundle onto a photodetector comprising a plurality of discrete photodetector elements. The output of the photodetector elements is utilized to determine a characteristic of the lighted or unlighted portion at the other end of the non-coherent fiber bundle, and the characteristic is used to determine a dimension, location, orientation, presence, or identity of the object or portion thereof.

Claims

1. A method of determining the dimension, location, orientation, presence, or identity of at least a portion of an object, said method comprising the steps of:

imaging at least a portion of an object onto an end of an at least partially non-coherent optical fiber bundle whereby the image incident on said end of said fiber bundle is transmitted to the other end thereof;

transferring said image from said other end of said non-coherent optical fiber bundle onto a photodetector comprising a plurality of discrete photodetector elements;

determining, from the output of said photodetector elements, a characteristic of the lighted or unlighted portion at the other end of said non-coherent fiber bundle; and

determining, from said characteristic, said dimension, location, orientation, presence, or identity of at least said portion of said object.

2. A method according to claim 1 wherein said characteristic comprises a distinctive signature produced by the particular object.

3. A method according to claim 2 wherein said signature is compared with a reference signature.

4. A method according to claim 3 wherein said object is a part and the signature of a part is analyzed to determine whether that part is threaded or not by detecting the differences between the signatures of threaded and unthreaded parts.

5. A method according to claim 2 wherein said object is a part and a characteristic signature is produced for a "good" part with which a comparison is made to determine whether the part under test is "good".

6. A method according to claim 5 wherein the area of an individual photodetector is not more than one-fifth of the cross sectional area of said individual fiber.

7. A method according to claim 1 wherein said transferring step comprises imaging the other end of said non-coherent fiber bundle on said photodetector.

8. A method according to claim 7 wherein said photodetector comprises a solid state photodetector array.

9. A method according to claim 8 wherein said photodetector comprises a matrix array.

10. A method according to claim 1 wherein the area of the individual photodetectors making up said photodetectors is less than the cross sectional area of each individual fiber in said bundle.

11. A method according to claim 1 wherein said photodetector comprises at least 20 discrete photodetector elements.

12. A method according to claim 1 wherein said image transferring step comprises locating said photodetector in close proximity to said other end of said fiber optical bundle without the interposition of a lens therebetween, whereby the light from said other end of said optical fiber bundle is transmitted directly thereto.

13. A method according to claim 1 wherein the fibers in either of said fiber bundle ends are arranged in at least one row.

14. A method according to claim 1 wherein said object comprises an edge and wherein said imaging step comprises imaging said edge of said end of said non-coherent fiber bundle.

15. A method according to claim 1 wherein said step of imaging comprises illuminating said object with fiber optic illuminating means.

16. A method according to claim 1 wherein said object comprises a tool.

17. A method according to claim 1 further comprising sensing the intensity of light making up said object image, and utilizing the sensed intensity to set threshold limits for determining light intensity characteristics at said other end of said non-coherent fiber bundle.

18. A method according to claim 1 further comprising detecting the intensity distribution of light at said other end of said fiber bundle for a given object or object position, an utilizing said intensity distribution of light at said other end of said fiber bundle for a given object or object position, and utilizing said intensity distribution at a later time to determine if said given object or object portion is present.

19. A method according to claim 1 further comprising contacting said object and a part at a point and utilizing the position of another point of said object to determine the dimension or location of said part.

20. A method according to claim 1 wherein said imaging stop comprises providing a plurality of images of said object onto said end of said non-coherent fiber bundle.

21. A method according to claim 1 further comprising pulsing a light to freeze said image of said object.

22. A method according to claim 1 wherein said object is among a plurality of objects in a feed track, wherein orientation of said objects in said feed track is determined, and further comprising directing mis-oriented objects to a reservoir for reintroduction into said feed track.

23. A method according to claim 1 wherein said fiber bundle is a plastic type.

24. A method according to claim 1 wherein said object is one or more holes.

25. A method according to claim 1 wherein said object is threaded.

26. A method according to claim 1 wherein said imaging comprises illuminating said object with reflected light and imaging with a lens and wherein the axis of illuminating light is disposed at an angle with respect to the lens axis, and wherein said method includes the further step of determining the proximity of said object relative to said lens or to a light source used for illuminating.

27. A method according to claim 1 wherein repeated images of different objects or positions of the same object are memorized.

28. A method according to claim 27 wherein the object is at least one test pattern.

29. A method according to claim 1 wherein the ends of the fibers at one end of said bundle are in alignment.

30. A method according to claim 1 wherein said fiber bundle is in the form of a ribbon comprising a row of fibers.

31. A method according to claim 30 wherein said fiber bundle comprises a plurality of said ribbons laminated together.

32. A method according to claim 1 wherein said fiber bundle comprises a plurality of discrete fiber bundles.

33. A method according to claim 1 further comprising utilizing said determined dimension, location, presence or identity to control a machine.

34. A method according to claim 1 wherein said object comprises a liquid spray.

35. A method according to claim 1 wherein said object comprises an intruder, a flame or smoke in a monitored zone.

36. A method according to claim 1 wherein said end of said fiber optic bundle is mounted on a gripper or arm of a robot.

37. A method according to claim 1 wherein said optical fiber bundle comprises up to about 30% randomly non-aligned optical fibers.

38. A method according to claim 1 wherein said optical fiber bundle comprises about 20 to 30% randomly non-aligned optical fibers.

39. Apparatus for determining the dimension, location, orientation, presence or identity of at least a portion of an object comprising:

means for imaging at least a portion of an object onto an end of an at least partially non-coherent optical fiber bundle whereby the image incident on said end of said fiber bundle is transmitted to the other end thereof;

means for transferring said image from said other end of said non-coherent optical fiber bundle onto a photodetector comprising a plurality of discrete photodetector elements;

means for determining, from the output of said photodetector elements, a characteristic of the lighted or unlighted portion at the other end of said non-coherent optical fiber bundle; and

means for determining, from said characteristic, said dimension, location, orientation, presence or identity of at least said portion of said object.

40. Apparatus according to claim 39 wherein said characteristic comprises a distinctive signature produced by the particular object.

41. Apparatus according to claim 40 further comprising means for comparing said signature with a reference signature.

42. Apparatus according to claim 40 wherein said object is a part and a characteristic signature is produced for a "good" part and means are provided for comparing the signature of the part under test with the signature of a "good" part so as to determine whether the part under test is "good".

43. Apparatus according to claim 42 wherein said object is a part and means are provided for analyzing the signature of a part to determine whether that part is threaded or not by detecting the differences between the signatures of threaded and unthreaded parts.

44. Apparatus according to claim 39 wherein said optical fiber bundle comprises up to about 30% randomly non-aligned optical fibers.

45. Apparatus according to claim 39 wherein said optical fiber bundle comprises about 20 to 30% randomly non-aligned optical fibers.

46. Apparatus according to claim 39 wherein said image transferring means comprises means for imaging the other end of said non-coherent fiber bundle on said photodetector.

47. Apparatus according to claim 39 wherein said photodetector comprises a solid state photodetector array.

48. Apparatus according to claim 47 wherein said photodetector comprises a matrix array.

49. Apparatus according to claim 39 wherein the area of the individual photodetectors making up said photodetectors is less than the cross sectional area of each individual fiber in said bundle.

50. Apparatus according to claim 39 wherein the area of an individual photodetector is not more than one-fifth of the cross sectional area of said individual fiber.

51. Apparatus according to claim 39 wherein said photodetector comprises at least 20 discrete photodetector elements.

52. Apparatus according to claim 39 wherein said image transferring means comprising means for locating said photodetector in close proximity to said other end of said fiber optical bundle without the interposition of a lens therebetween, whereby the light from said other end of said non-coherent optical fiber bundle is transmitted directly thereto.

53. Apparatus according to claim 52 wherein said photodetector is affixed to said other end of said non-coherent optical fiber bundle.

54. Apparatus according to claim 39 wherein the fibers in either of said fiber bundle ends are arranged in at least one row.

55. Apparatus according to claim 39 wherein said object comprises an edge and wherein said imaging means comprises means for imaging said edge on said end of said non-coherent fiber bundle.

56. Apparatus according to claim 39 wherein said means for imaging comprises fiber optic means for illuminating said object.

57. Apparatus according to claim 39 further comprising means for sensing the intensity of light making up said object image, and means for utilizing the sensed intensity to set threshold limits for determining light intensity characteristics at both ends of said non-coherent fiber bundle.

58. Apparatus according to claim 39 further comprising means for determining the intensity distribution at a later time to determine if said given object or object portion is present.

59. Apparatus according to claim 39 wherein said imaging means comprises providing a plurality of images of said object onto said end of said non-coherent fiber bundle.

60. Apparatus according to claim 39 further comprising means for pulsing a light to freeze said image of said object.

61. Apparatus according to claim 39 further comprising feed track means for feeding a plurality of objects, wherein said determining mean comprises means for determining orientation of an object in said feed track, and further comprising means for directing mis-oriented objects to a reservoir for reintroduction into said feed track.

62. Apparatus according to claim 39 wherein said fiber bundle is a plastic type.

63. Apparatus according to claim 39 further comprising means for memorizing repeated images of different objects or positions of the same object.

64. Apparatus according to claim 39 wherein the ends of the fibers at one end of said fiber bundle are in alignment.

65. Apparatus according to claim 39 wherein said fiber bundle is in the form of a ribbon comprising a row of fibers.

66. Apparatus according to claim 65 wherein said fiber bundle comprises a plurality of said ribbons laminated together.

67. Apparatus according to claim 39 wherein said fiber bundle comprises a plurality of discrete fiber bundles.

68. Apparatus according to claim 39 further comprising means for utilizing said determined dimension, location, presence or identity to control a machine.

69. Apparatus according to claim 39 further comprising means for utilizing said determined dimension, location, presence or identity to control machine.

70. Apparatus according to claim 39 wherein said means for determining said object dimension, location, orientation, presence, or identity comprises a microcomputer.

71. A method according to claim 39 wherein said photodetector is affixed to said other end of said optical fiber bundle.