METHOD AND APPARATUS FOR REMOTE SENSING OF OBJECTS UTILIZING RADIATION SPECKLE

• US 20080154524A1
• Filed: 06/16/2007
• Published: 06/26/2008
• Est. Priority Date: 06/16/2006
• Status: Active Grant

• Current Assignee: Lyle G. Shirley
• Original Assignee: Lyle G. Shirley
• Inventors: Shirley, Lyle G.
• Granted Patent: US 8,265,375 B2
• Time in Patent Office: Days
• US Class Current: 702/66
• CPC Class Codes: G01B 9/02004 using frequency scans
• CPC Class Codes: G01B 9/02069 Synchronization of light source or manipulator and detector
• CPC Class Codes: G01B 9/02083 characterised by particular signal processing and presentation
• CPC Class Codes: G01B 9/02096 detecting a contour or curvature
• CPC Class Codes: G06T 7/521 from laser ranging, e.g. using interferometry; from the projection of structured light

Abstract

Disclosed are systems and methods to extract information about the size and shape of an object by observing variations of the radiation pattern caused by illuminating the object with coherent radiation sources and changing the wavelengths of the source. Sensing and image-reconstruction systems and methods are described for recovering the image of an object utilizing projected and transparent reference points and radiation sources such as tunable lasers. Sensing and image-reconstruction systems and methods are also described for rapid sensing of such radiation patterns. A computational system and method is also described for sensing and reconstructing the image from its autocorrelation. This computational approach uses the fact that the autocorrelation is the weighted sum of shifted copies of an image, where the shifts are obtained by sequentially placing each individual scattering cell of the object at the origin of the autocorrelation space. This computational approach reconstructs the image by eliminating all but one of these copies.

Claims

1. An imaging apparatus, said imaging apparatus comprising:

at least one source of coherent radiation outputting a plurality of wavelengths illuminating an object creating a plurality of speckle patterns each corresponding to the plurality of wavelengths;

at least one sensor at a location relative to said object to determine the intensity of the speckle pattern for each of the plurality of wavelengths;

a processor receiving information from said at least one sensor, said processor having means for constructing at least one autocorrelation of said object from said intensities of said speckle pattern;

a controller for controlling the at least one source of coherent radiation creating a projected reference point; and

said processor further comprising means for executing a regional image selection technique to construct a representation of said object utilizing said projected reference point and said autocorrelation.

2. The imaging apparatus of claim 1 further comprising:

means for splitting said outputting of said plurality of wavelengths of coherent radiation into a first set of a plurality of wavelengths and a second set of a plurality of wavelengths;

means for delaying said outputting of one of said sets of a plurality of wavelengths relative to said outputting of the other set of a plurality of wavelengths; and

means for focusing one of said sets of a plurality of wavelengths creating a focused spot for use as said projected reference point.

3. The imaging apparatus of claim 2 wherein said source of coherent radiation comprises a tunable laser.

4. The imaging apparatus of claim 2 further comprising a means for moving the outputting of one of said sets of a plurality of wavelengths creating at least one projected reference point.

5. A method of constructing a representation of an object, said method comprising the steps of:

illuminating an object with at least one source of coherent radiation at a plurality of wavelengths creating a plurality of speckle patterns each corresponding to the plurality of wavelengths;

determining the intensity of the speckle pattern for each of the plurality of wavelengths with at least one sensor;

receiving information from said at least one sensor and constructing at least one autocorrelation of said object from said intensity of the speckle pattern;

controlling said at least one source of coherent radiation and creating a focused spot for use as a projected reference point; and

executing a regional image selection technique to construct a representation of said object utilizing said projected reference point and said autocorrelation.

6. The method of claim 5 wherein said controlling said at least once source of coherent radiation further comprises the steps of:

splitting said outputting of said plurality of wavelengths of coherent radiation into a first set of a plurality of wavelengths and a second set of a plurality of wavelengths;

delaying said outputting of one of said sets of a plurality of wavelengths relative to said outputting of the other set of a plurality of wavelengths; and

focusing one of said sets of a plurality of wavelengths creating said projected reference point.

7. The method of claim 6 wherein said coherent radiation source comprises a tunable laser.

8. The method of claim 6 further comprising the step of moving the outputting of one of said sets of a plurality of wavelengths creating at least one projected reference points.

9. An imaging apparatus, said imaging apparatus comprising:

at least one source of coherent radiation outputting a plurality of wavelengths illuminating an object creating a plurality of speckle patterns each corresponding to the plurality of wavelengths;

at least one sensor at a location relative to said object to determine the intensity of the speckle pattern for each of the plurality of wavelengths;

a processor receiving information from at least one sensor, said processor having means for constructing at least one autocorrelation of said object from said intensities of said speckle pattern;

a curved surface influencing said intensities and said speckle patterns creating a reference point; and

said processor further comprising means for executing a regional image selection technique to construct a representation of said object utilizing said projected reference point and said autocorrelation.

10. The imaging apparatus of claim 9 wherein said curved surface is transparent.

11. The imaging apparatus of claim 10 wherein said coherent radiation source comprises a tunable laser.

12. The imaging apparatus of claim 10 wherein said curved surface comprises the cornea of an eye.

13. The imaging apparatus of claim 10 wherein said curved surface comprises a lens.

14. The imaging apparatus of claim 9 wherein said coherent radiation source comprises a tunable laser.

15. A method of constructing a representation of an object, said method comprising the steps of:

illuminating an object with at least one source of coherent radiation at a plurality of wavelengths creating a plurality of speckle patterns each corresponding to the plurality of wavelengths;

determining the intensity of the speckle pattern for each of the plurality of wavelengths with at least one sensor;

receiving information from said at least one sensor and constructing at least one autocorrelation of said object from said intensity of the speckle pattern;

receiving said intensity and speckle pattern influenced by a curved surface creating a reference point; and

executing a regional image selection technique to construct a representation of said object utilizing said reference point and said autocorrelation.

16. The method of claim 15 wherein said curved surface is transparent.

17. The method of claim 16 wherein said coherent radiation source comprises a tunable laser.

18. The method of claim 16 wherein said curved surface comprises the cornea of an eye.

19. The method of claim 16 wherein said curved surface comprises a lens.

20. The method of claim 15 wherein said coherent radiation source comprises a tunable laser.

21. An imaging apparatus, said imaging apparatus comprising:

at least one source of coherent radiation outputting a plurality of wavelengths illuminating an object creating a plurality of speckle patterns each corresponding to the plurality of wavelengths;

at least one sensor at a location relative to said object to determine the intensity of the speckle pattern for each of the plurality of wavelengths;

a processor receiving information from at least one sensor, said processor having means for constructing at least one autocorrelation of said object from said intensities of said speckle pattern; and

said processor further comprising means to compare at least one of said autocorrelations.

22. The imaging apparatus of claim 21 wherein said processor further comprises means to compare said autocorrelation of said object to a second autocorrelation.

23. The imaging apparatus of claim 22 wherein:

said object comprises a partial representation of a representation of said object; and

said second autocorrelation comprises a stored autocorrelation of said partial representation.

24. The imaging apparatus of claim 22 wherein said processor further comprises means for recognizing changes between said autocorrelation of said object and said second autocorrelation.

25. The imaging apparatus of claim 21 further comprising:

more that one autocorrelation of said object; and

said processor further comprising means to rotate and compare one autocorrelation of said object relative to at least one other autocorrelation of said object to construct a representation of said object.

26. A method of constructing a representation of an object, said method comprising the steps of:

illuminating an object with at least one source of coherent radiation at a plurality of wavelengths creating a plurality of speckle patterns each corresponding to the plurality of wavelengths;

determining the intensity of the speckle pattern for each of the plurality of wavelengths with at least one sensor;

receiving information from said at least one sensor and constructing at least one autocorrelation of said object from said intensity of the speckle pattern; and

comparing said autocorrelations.

27. The method of claim 26 further comprising the step of comparing said autocorrelation of said object to a second autocorrelation.

28. The method of claim 27 wherein:

said object comprises a partial representation of a representation of said object; and

said second autocorrelation comprises a stored autocorrelation of said partial representation.

29. The method of claim 27 further comprising the step of recognizing changes between said autocorrelation of said object and said second autocorrelation.

30. The method of claim 26 further comprising the step of rotating and comparing one autocorrelation of said object relative to at least one other autocorrelation of said object to construct a representation of said object.

31. A system for constructing a representation of an object from an autocorrelation, said system comprising:

an autocorrelation comprising a copy wherein said copy comprises autocorrelation points representing an object;

said autocorrelation further comprising autocorrelation points that lie on said copy and autocorrelation points that do not lie on said copy; and

a processor comprising means to shift and compare said autocorrelation points eliminating said autocorrelation points that do not lie on said copy constructing a representation of said object from said autocorrelation points that lie on said copy.

32. The system of claim 31 wherein said means to shift and compare further comprises:

means to select at least one shift candidate comprising autocorrelation points that lie on said copy;

means to shift said autocorrelation to said shift candidates creating a shifted autocorrelation;

means to compare said shifted autocorrelation with said autocorrelation and eliminate said autocorrelation points that do not lie on said copy creating a partial reconstruction of said copy;

means to update said partial reconstruction of said copy further comprising;

means to select at least one additional shift candidate,

means to shift said autocorrelation to said additional shift candidates creating a second shifted autocorrelation and

means to compare said second shifted autocorrelation with said partial reconstruction of said copy and eliminate autocorrelation points that do not lie on said copy creating an update to said partial reconstruction of said copy; and

means to repeat the foregoing means to update said partial reconstruction of said copy until said partial reconstruction of said copy comprises a representation of said object.

33. The system of claim 32 wherein said means to shift and compare further comprises:

processing operations of said autocorrelation to select preferred shift candidates comprising autocorrelation points that lie on said copy; and

said processing operations selected from the group consisting of;

locating local peaks,

locating points on bright copies,

locating perimeter points,

locating points producing fewer survivors,

locating points producing large separation of copies and

locating points from infrequent interference events.

34. The system of claim 32 wherein said means to shift and compare further comprise compare operations of said autocorrelation selected from the group consisting of:

a minimum operation,

an intersect operation and

a brightness ranking operation.

35. The system of claim 32 wherein said means to shift and compare further comprises means to select at least one additional shift candidate selected from the group of means to select shift candidates consisting of:

means to select preferred shift candidates;

means to select bright points in partial reconstruction;

opacity constraint;

geometrical assumptions; and

vector matching.

36. The system of claim 32 further comprising:

at least one source of coherent radiation outputting a plurality of wavelengths illuminating an object creating a plurality of said speckle patterns each corresponding to the plurality of wavelengths;

at least one sensor at a location relative to said object to determine the intensity of the speckle pattern for each of the plurality of wavelengths;

a processor receiving information from at least one sensor, said processor having means for constructing at least one autocorrelation of said object from said intensities of said speckle pattern; and

said processor comprising means to output said representation of said object.

37. The imaging apparatus of claim 31 wherein said means to shift and compare further comprise means to select shift candidates that are self-consistent.

38. The imaging apparatus of claim 37 wherein said means to shift and compare further comprise means to:

form a consistency matrix comprising autocorrelation points;

reorder said consistency matrix to identify self-consistent shift candidates; and

shift said autocorrelation and compare with said autocorrelation creating a partial reconstruction of said copy.

39. A method to construct a representation of an object from an autocorrelation, said method comprising the steps of:

shifting and comparing autocorrelation points of an autocorrelation, said autocorrelation comprising autocorrelation points that lie on a copy comprising autocorrelation points representing an object and autocorrelation points that do not lie on said copy; and

eliminating autocorrelation points that do not lie on said copy constructing a representation of said object from said autocorrelation points that lie on said copy.

40. The method of claim 39 wherein said shifting and comparing further comprises the steps of:

selecting at least one shift candidate comprising autocorrelation points that lie on said copy;

shifting said autocorrelation to said shift candidates creating a shifted autocorrelation;

comparing said shifted autocorrelation with said autocorrelation and eliminating said autocorrelation points that do not lie on said copy creating a partial reconstruction of said copy;

updating said partial reconstruction of said copy with steps further comprising;

selecting at least one additional shift candidate,

shifting said autocorrelation to said additional shift candidates creating a second shifted autocorrelation and

comparing said second shifted autocorrelation with said partial reconstruction of said copy and eliminating autocorrelation points that do not lie on said copy creating an update to said partial reconstruction of said copy; and

repeating the foregoing steps to update said partial reconstruction of said copy until said partial reconstruction of said copy comprises a representation of said object.

41. The method of claim 40 further comprising the step of processing said autocorrelation to select preferred shift candidates wherein said processing is selected from the group of steps consisting of:

locating local peaks,

locating points on bright copies,

locating perimeter points,

locating points producing fewer survivors,

locating points producing large separation of copies and

locating points from infrequent interference events.

42. The method of claim 40 further comprising the step of comparing said autocorrelation wherein said comparing is selected from the group of operations consisting of:

a minimum operation,

an intersect operation and

a brightness ranking operation.

43. The method of claim 40 further comprising the step of selecting at least one additional shift wherein said means to select said additional shift is selected from the group of means to select shifts consisting of:

means to select preferred shifts;

means to select bright points in partial reconstruction;

opacity constraint;

geometrical assumptions; and

vector matching.

44. The method of claim 40 further comprising the steps of:

illuminating an object with at least one source of coherent radiation at a plurality of wavelengths creating a plurality of speckle patterns each corresponding to the plurality of wavelengths;

determining the intensity of the speckle pattern for each of the plurality of wavelengths with at least one sensor;

receiving information from said at least one sensor and constructing at least one autocorrelation of said object from said intensity of the speckle pattern; and

outputting said representation of said object.

45. The method of claim 39 further comprising the step of selecting shift candidates that are self-consistent.

46. The method of claim 45 further comprising the step of:

forming a consistency matrix comprising autocorrelation points;

reordering said consistency matrix to identify self-consistent shift candidates; and

shifting said autocorrelation and comparing with said autocorrelation creating a partial reconstruction of said copy.

47. An imaging apparatus, said imaging apparatus comprising:

At least one source of coherent radiation outputting a plurality of wavelengths illuminating an object creating a plurality of speckle patterns each corresponding to the plurality of wavelengths;

At least one sensor at a location relative to said object to determine the intensity of the speckle pattern for each of the plurality of wavelengths;

said source of coherent radiation rapidly outputting said plurality of wavelengths;

means to associate the outputting of each of said plurality of wavelengths from said radiation source with the receipt of corresponding intensities of the speckle pattern for each of the plurality of wavelengths at said at least one sensor; and

a processor receiving information from said at least one sensor, said processor having means for constructing at least one autocorrelation of said object from said intensities of said speckle pattern.

48. The imaging apparatus of claim 47 wherein said means to associate the outputting of each of said plurality of wavelengths from said radiation source with the receipt of corresponding intensities of the speckle pattern at said sensor comprises timing means to synchronize said outputting of said plurality of wavelengths and said receipt of corresponding intensities of the speckle pattern.

49. The imaging apparatus of claim 48 wherein said timing means further comprises a timing clock communicating at least one synchronized timing signal with said sensor and said coherent radiation source.

50. A method of constructing a representation of an object, said method comprising the steps of:

illuminating an object with at least one source of coherent radiation at a plurality of wavelengths creating a plurality of speckle patterns each corresponding to the plurality of wavelengths;

determining the intensity of the speckle pattern for each of the plurality of wavelengths with at least one sensor;

receiving information from said at least one sensor and constructing at least one autocorrelation of said object from said intensity of the speckle pattern;

rapidly outputting said plurality of wavelengths;

associating the outputting of each of said plurality of wavelengths from said radiation source with the receipt of corresponding intensities of the speckle pattern for each of the plurality of wavelengths at said at least one sensor; and

constructing at least one autocorrelations of said object from said intensities of said speckle pattern.

51. The method of claim 50 wherein said associating the outputting of each of said plurality of wavelengths from said radiation source with the receipt of corresponding intensities of the speckle pattern at said sensor comprises synchronizing said outputting of said plurality of wavelengths and said receipt of corresponding intensities of the speckle pattern by time.

52. The method of claim 51 wherein said synchronizing said outputting of said plurality of wavelengths and said receipt of corresponding intensities of the speckle pattern by time further comprises a timing clock.