Electro-optical sensors with fiber optic bundles

• US 4,441,817 A
• Filed: 07/29/1980
• Issued: 04/10/1984
• Est. Priority Date: 07/29/1980
• Status: Expired due to Term

• Current Assignee: Diffracto, Ltd. (LMI Technologies Inc.)
• Original Assignee: Diffracto, Ltd. (LMI Technologies Inc.)
• Inventors: Pryor, Timothy R.
• Primary Examiner(s): Rosenberger, R. A.
• Application Number:
  US06/173,370
• Time in Patent Office: 1,351 Days
• Field of Search: 250/227, 250/578, 350/96.24, 356/372, 356/373, 356/375, 356/376, 356/379, 356/384
• 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 250/902 with closed light path preset

Abstract

Method and apparatus for determining physical characteristics of an object, such as its location, utilizing a non-coherent fiber optic bundle. In one embodiment, a non-coherent fiber optic bundle containing up to 30% randomly non-aligned fibers is utilized and an object is imaged onto one end of the bundle and the image is transferred from the other end of the bundle to a photodetector comprising a plurality of discrete photodetector elements. The area of the lighted or unlighted portion at the other end of the bundle is utilized to determine the physical characteristics of the object.

Claims

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

imaging at least a portion of an object onto an end of a 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, the area of the lighted or unlighted portion at the other end of said non-coherent optical fiber bundle; and

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

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

3. A method according to claim 2 wherein said photodetector comprises a solid state photodetector array.

4. A method according to claim 3 wherein said photodetector comprises a matrix array.

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

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 photodetector comprises at least 20 discrete photodetector elements.

8. 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 non-coherent optical fiber bundle is transmitted directly thereto.

9. A method according to claim 8 wherein said photodetector is affixed to said other end of said non-coherent optical fiber bundle.

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

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

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

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

14. 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.

15. A method according to claim 1 further comprising detecting the intensity distribution of light at said other end of said non-coherent 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.

16. 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.

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

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

19. 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.

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

21. A method according to claim 1 wherein said object has one or more holes.

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

23. 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.

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

25. A method according to claim 24 wherein the object is at least one test pattern.

26. A method according to claim 1 wherein the ends of the fibers at one or both ends of said bundle are in alignment.

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

28. A method according to claim 27 wherein said fiber bundle comprises a plurality of said ribbons laminated together.

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

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

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

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

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

34. Apparatus for determining the dimension, location, orientation, presence or identiy of at least a portion of an object comprising;

means for imaging at least a portion of an object onto an end of a 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, the area of the lighted or unlighted portion at the other end of said non-coherent optical fiber bundle; and

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

35. Apparatus according to claim 34 wherein said image transferring means comprises means for imaging the other end of said non-coherent fiber bundle on said photodetector.

36. Apparatus according to claim 35 wherein said photodetector comprises a solid state photodetector array.

37. Apparatus according to claim 36 wherein said photodetector comprises a matrix array.

38. Apparatus according to claim 34 wherein the area of the individual photodetectors making up said photodetector is less than the cross sectional area of each individual fiber in said bundle.

39. Apparatus according to claim 38 wherein the area of an individual photodetector is not more than one-fifth of the cross sectional area of said individual fiber.

40. Apparatus according to claim 34 wherein said photodetector comprises at least 20 discrete photodetector elements.

41. Apparatus according to claim 34 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 noncoherent optical fiber bundle is transmitted directly thereto.

42. Apparatus according to claim 41 wherein said photodetector is affixed to said other end of said non-coherent optical fiber bundle.

43. Apparatus according to claim 34 wherein the fibers in either of said fiber bundle ends are arranged in at least one row.

44. Apparatus according to claim 34 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.

45. Apparatus according to claim 34 wherein said means for imaging comprises fiber optic means for illuminating said object.

46. Apparatus according to claim 34 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.

47. Apparatus according to claim 34 further comprising means for detecting the intensity distribution of light at said other end of said non-coherent fiber bundle for a given object or object position, and means for utilizing said intensity distribution at a later time to determine if said given object or object portion is present.

48. Apparatus according to claim 34 wherein said imaging means comprises providing a plurality of images of said object onto said end of said non-coherent fiber bundle.

49. Apparatus according to claim 34 further comprising means for pulsing a light to freeze said image of said object.

50. Apparatus according to claim 34 further comprising feed track means for feeding a plurality of objects, wherein said determining means 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.

51. Apparatus according to claim 34 wherein said fiber bundle is a plastic type.

52. Apparatus according to claim 34 further comprising means for memorizing repeated images of different objects or of different positions of the same object.

53. Apparatus according to claim 34 wherein the ends of the fibers at one or both ends of said fiber bundle are in alignment.

54. Apparatus according to claim 34 wherein said fiber bundle is in the form of a ribbon comprising a row of fibers.

56. Apparatus according to claim 34 wherein said fiber bundle comprises a plurality of discrete fiber bundles.

57. Apparatus according to claim 34 further comprising means for utilizing said determined dimension, location, presence or identity to control a machine.

58. Apparatus according to claim 34 wherein said end of said fiber optic bundle is mounted on a gripper or arm of a robot.

59. Apparatus according to claim 34 wherein said means for determining said object dimension, location, orientation, presence, or identity comprises a microcomputer.

55. Apparatus according to claim 105 wherein said fiber bundle comprises a plurality of said ribbons laminated together.