Phase coding technique for one-way image transmission through an aberrating medium

• US 5,555,128 A
• Filed: 10/04/1994
• Issued: 09/10/1996
• Est. Priority Date: 10/04/1994
• Status: Expired due to Fees

• Current Assignee: Government of The United States As Represented By The U.S. Air Force (Government of the United States of America), United States Air Force
• Original Assignee: United States Of America As Represented By The Secretary Of The Air Force
• Inventors: Fu, Jack, Khoury, Jehad, Woods, Charles L.
• Primary Examiner(s): Callahan, Timothy P.
• Assistant Examiner(s): LAM, TUAN THIEU
• Application Number:
  US08/319,144
• Time in Patent Office: 707 Days
• Field of Search: 359/7, 359/10, 359/11, 359/16, 359/559
• US Class Current: 359/559
• CPC Class Codes: G03H 1/00 Holographic processes or apparatus using light, infrared or ultraviolet waves for obtaining holograms or for obtaining an image from them; Details peculiar thereto

Abstract

An object beam is passed through an aberrating medium to produce a diffraction distorted image therein, which is imaged upon a spatial light modulator. A probe beam measures the phase aberrated wavefront within the aberrating medium and is used to produce an interference pattern which is employed to produce phase encoding signals to be fed back to the spatial light modulator for compensating in part for the phase distortion of the phase aberrated wavefront. The result is an output image having a substantially reduced degree of distortion.

Claims

1. Apparatus for performing one way image restoration of an image which is projected through a phase aberrating medium comprising:

(a) first beam projection means for projecting an object beam having a first polarization through the phase aberrating medium to produce a diffraction distorted image therein;

(b) second beam projection means for projecting a phase aberration measurement probe beam having a second polarization through the phase aberrating medium to produce a phase aberrated wavefront therein;

(c) beam separation means for separating the object beam from the probe beam;

(d) first imaging means for imaging the diffraction distorted image contained within said object beam upon an image receptor;

(e) second imaging means for imaging the phase aberrated wavefront contained within said probe beam upon an image sensor;

(f) interference pattern generation means for combining the probe beam with a reference beam for in turn producing an interference pattern upon the image sensor; and

(g) phase encoding means, coupled between the image sensor and the image receptor, for producing a phase encoded signal upon the image receptor which compensates for part of the phase distortion of the phase aberrated wavefront in its first order approximation.

2. The apparatus of claim 1 wherein said beam separation means comprises a polarizing beam splitter.

3. The apparatus of claim 1 wherein said image receptor comprises a spatial light modulator.

4. The apparatus of claim 2 wherein said image receptor comprises a spatial light modulator.

5. The apparatus of claim 1 wherein said image sensor comprises a gray scale detector.

6. The apparatus of claim 2 wherein said image sensor comprises a gray scale detector.

7. The apparatus of claim 3 wherein said image sensor comprises a gray scale detector.

8. The apparatus of claim 4 wherein said image sensor comprises a gray scale detector.

9. The apparatus of claim 5 wherein said phase encoding means produces phase encoded signals that are a function of the light intensity sensed by the gray scale detector.

10. The apparatus of claim 7 wherein said phase encoding means produces phase encoded transfer function signals that are a function of the light intensity sensed by the gray scale detector.

11. Apparatus for performing one way image restoration of an image which is projected through a phase aberrating medium comprising:

(a) first beam projection means for projecting an object beam through the phase aberrating medium for producing a diffraction distorted image therein;

(b) second beam projection means for projecting a phase aberration measurement probe beam through the phase aberrating medium to produce a phase aberrated wavefront therein;

(c) beam separation means for separating the object beam from the probe beam;

(d) first imaging means for imaging the diffraction distorted image contained within said object beam upon an image receptor;

(d1) second imaging means for imaging the phase aberrated wavefront contained in said probe beam upon an image sensor;

(e) phase retardation sensing means for detecting local wavefront distortions produced by the phase aberrating medium; and

(f) phase encoding means, coupled between the phase retardation sensing means and the image receptor, for producing a phase encoded signal upon the image receptor which compensates for part of the phase distortion of the phase aberrated wavefront in its first order approximation.

12. The apparatus of claim 11 wherein said beam separation means comprises a polarizing beam splitter.

13. The apparatus of claim 11 wherein said image receptor comprises a spatial light modulator.

14. The apparatus of claim 12 wherein said image receptor comprises a spatial light modulator.

15. The apparatus of claim 11 wherein said image sensor comprises a gray scale detector.

16. The apparatus of claim 12 wherein said image sensor comprises a gray scale detector.

17. The apparatus of claim 13 wherein said image sensor comprises a gray scale detector.

18. The apparatus of claim 14 wherein said image sensor comprises a gray scale detector.

19. The apparatus of claim 15 wherein said phase encoding means produces phase encoded signals that are a function of the light intensity sensed by the gray scale detector.

20. The apparatus of claim 17 wherein said phase encoding means produces phase encoded transfer function signals that are a function of the light intensity sensed by the gray scale detector.

21. Apparatus for performing one way image restoration of an image which is projected through a phase aberrating medium comprising:

(a) first beam projection means for projecting an object beam through the phase aberrating medium for producing a diffraction distorted image therein;

(b) second beam projection means for projecting a phase aberration measurement probe beam through the phase aberrating medium to produce a phase aberrated wavefront therein;

(c) beam separation means for separating the object beam from the probe beam;

(d) first imaging means for imaging the diffraction distorted image contained within said object beam upon an image receptor;

(d1) second imaging means for imaging the phase aberrated wavefront contained in said probe beam upon an image sensor;

(e) local wavefront sensing means for detecting optical path length distortions produced by the phase aberrating medium; and

(f) phase encoding means, coupled between the local wavefront sensing means and the image receptor, for producing a phase encoded signal upon the image receptor which compensates for part of the phase distortion of the phase aberrated wavefront in its first order approximation.