Method and apparatus for remote sensing of objects utilizing radiation speckle

• US 8,265,375 B2
• Filed: 06/16/2007
• Issued: 09/11/2012
• Est. Priority Date: 06/16/2006
• Status: Active Grant

• Current Assignee: Lyle G. Shirley
• Original Assignee: Lyle G. Shirley
• Inventors: Shirley, Lyle G.
• Primary Examiner(s): DULANEY, KATHLEEN YUAN
• Application Number:
  US11/764,196
• Publication Number:
  US 20080154524A1
• Time in Patent Office: 1,914 Days
• Field of Search: 382/154, 396/51, 356/600, 702/172
• US Class Current: 382/154
• 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 a speckle pattern intensity 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 first portion of said coherent radiation passing through a curved surface;

a second portion of said coherent radiation being reflected by said curved surface creating a reference point;

said reference point is a virtual spot of focused coherent radiation producing a copy in said autocorrelation;

said virtual spot of focused coherent radiation is located behind the curved surface; and

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

2. The imaging apparatus of claim 1 wherein said copy is offset in range in said autocorrelation.

3. The imaging apparatus of claim 1 wherein said curved surface comprises the cornea of an eye.

4. The imaging apparatus of claim 1 wherein said curved surface comprises a lens.

5. 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 a speckle pattern intensity 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 first portion of said coherent radiation passing through a curved surface;

a second portion of said coherent radiation being reflected by said curved surface creating a reference point;

said reference point is a virtual spot of focused coherent radiation producing a copy in said autocorrelation;

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

said coherent radiation source being incident on said curved surface;

said curved surface lying in front of said object; and

said first portion of said coherent radiation illuminating said object.

6. The imaging apparatus of claim 5 wherein said copy is offset in range in said autocorrelation.

7. The imaging apparatus of claim 5 wherein said curved surface comprises the cornea of an eye.

8. The imaging apparatus of claim 5 wherein said curved surface comprises a lens.

9. 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 a speckle pattern intensity 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;

passing a first portion of said coherent radiation through a curved surface;

receiving a portion of said coherent radiation reflected by the curved surface creating a reference point;

said reference point is a virtual spot of focused coherent radiation producing a copy in said autocorrelation;

said virtual spot of focused coherent radiation is location behind the curved surface; and

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

10. The method of claim 9 wherein said copy is offset in range in said autocorrelation.

11. The method of claim 9 wherein said curved surface comprises the cornea of an eye.

12. The method of claim 9 wherein said curved surface comprises a lens.

13. A method of constructing a representation of as 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 pattern each corresponding to the plurality of wavelengths;

determining a speckle pattern intensity 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;

passing a first portion of said coherent radiation through a curved surfaced;

receiving a portion of said coherent radiation reflected by the curved surface creating a reference point;

said reference point is a virtual spot of focused coherent radiation producing a copy in said autocorrelation;

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

said coherent radiation source being incident on said curved surface;

said curved surface lying in front of said object; and

said first portion of said coherent radiation illuminating said object.

14. The method of claim 13 wherein said copy is offset in range in said autocorrelation.

15. The method of claim 13 wherein said curved surface comprises the cornea of an eye.

16. The method of claim 13 wherein said curved surface comprises a lens.