Optical stereo video signal processor

• US 4,556,986 A
• Filed: 03/09/1983
• Issued: 12/03/1985
• Est. Priority Date: 03/09/1983
• Status: Expired due to Fees

• Current Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Original Assignee: United States Of America As Represented By The Administrator Of The National Aeronautics And Space Administration
• Inventors: Craig, Glenn D.
• Primary Examiner(s): Boudreau, Leo H.
• Application Number:
  US06/473,499
• Time in Patent Office: 1,000 Days
• Field of Search: 350/384, 350/385, 350/386, 350/335, 350/3.67, 350/162.13, 350/162.14, 350/130, 356/4.5, 356/10, 356/356, 356/4, 356/5, 356/12, 356/373, 356/375, 356/345, 358/125, 358/2, 358/3, 358/105, 358/88, 358/90, 382/42, 364/822
• US Class Current: 382/106
• CPC Class Codes: G01C 11/06 by comparison of two or more pictures of the same area
• CPC Class Codes: G01S 17/46 Indirect determination of position data
• CPC Class Codes: G01S 7/4912 Receivers

Abstract

An optical video signal processor which produces a two-dimensional cross-correlation in real time of images received by a stereo camera system. The optical image of each camera (12, 14) is projected on respective liquid crystal light valves (28, 48). The images on the liquid crystal valves (28, 48) modulate light produced by an extended light source (32). This modulated light output becomes the two-dimensional cross-correlation when focused onto a video detector (42) and is a function of the range of a target (1) with respect to the stereo camera (10). Alternate embodiments utilize the two-dimensional cross-correlation to determine target movement and target identification.

Claims

1. A method for obtaining parallax data, such as the range of a particular target, including the steps of:

(a) producing first and second representations of the target, the first representation being slightly offset from said second representation;

(b) displaying said first and second representations of the target, on respective first and second displays;

(c) directing a polarized and collimated beam of light at the output planes of a first liquid crystal light valve and a second liquid crystal light valve;

(d) directing the information provided on the face of said first display to the input plane of said first liquid crystal light valve and the information provided on the face of said second display to the input plane of a second liquid crystal light valve, said present step being performed simultaneously with directing the polarized and collimated beam of light at the output planes of said first and second liquid crystal light valve;

(e) superimposing the images produced on the output planes of said first and second liquid crystal light valves on a video detector, wherein the images produced on the output planes of said first and second liquid crystal light valves are proportional to the images impressed on the input planes of said first and second liquid crystal light valves; and

(f) producing a peak correlation signal on said video detector, said peak correlation signal being indicative of the range of the target.

2. The method in accordance with claim 1 wherein said first and second representations are produced by first and second video cameras.

3. The method in accordance with claim 1 wherein said first and second representations are produced by charge coupled silicon devices.

4. A method for determining tracking information for a particular target, including the steps of:

(a) producing a first and second representation of the target, the first representation being slightly offset from said second representation;

(b) storing either said first or said second representation of said target in a storage device and continuously providing the other representation;

(c) displaying said stored representation and said continuously provided representation on respective first and second displays;

(d) directing a polarized and collimated beam of light at the output planes of a first liquid crystal light valve and a second liquid crystal light valve;

(e) directing the information provided on the face of said first display to the input plane of said first liquid crystal light valve and the information provided on the face of said second display to the input plane of a second liquid crystal light valve, said present step being performed simultaneously with directing the polarized and collimated beam of light at the output planes of said first and second liquid crystal light valve;

(f) superimposing the images produced on the output planes of said first and second liquid crystal light valves on a video detector, wherein the images produced on the output planes of said first and second liquid crystal light valves are proportional to the images impressed on the input planes of said first and second liquid crystal light valves;

(g) producing a peak correlation signal on said video detector, whereby any movement of said peak correlation signal indicates movement of the target, the movement of said signal on said video detector being proportional to the actual movement of the target.

5. The method in accordance with claim 4 wherein said first and second representations are produced by first and second video cameras.

6. The method in accordance with claim 4 wherein said first and second representations are produced by charge coupled silicon devices.

7. A method for identifying a particular unknown target, including the steps of:

(a) providing a plurality of possible target images in a video playback system;

(b) producing a representation of the unknown target;

(c) displaying said representation of the unknown target and one of the possible target images included in said video playback system on respective first and second displays;

(d) directing a polarized and collimated beam of light at the output planes of a first liquid crystal light valve and a second liquid crystal light valve;

(e) directing the information provided on the face of said first display to the input plane of said first liquid crystal light valve and the information provided on the face of said second display to the input plane of a second liquid crystal light valve, said present step being performed simultaneously with directing the polarized and collimated beam of light at the output planes of said first and second liquid crystal light valve;

(f) superimposing the images produced on the output planes of said first and second liquid crystal light valves on a video detector, wherein the images produced on the output planes of said first and second liquid crystal light valves are proportional to the images impressed on the input planes of said first and second liquid crystal light valves; and

(g) repetitively correlating the representation of the unknown target with successive images provided on said video playback system in a trial and fit basis until the unknown target has been sufficiently classified.

8. An optical stereo video signal processor comprising:

(a) a stereo camera system including first and second video cameras;

(b) first display means in communication with said first video camera, and second display means in communication with said second video camera for producing an optical representation of an image detected from its respective video camera;

(c) a first liquid crystal light valve in optical communication with said first display means, and a second liquid crystal light valve in optical communication with said second display means, each of said first and second liquid crystal light valves including an input plane directed at its respective first and second display means and each of said first and second liquid crystal light valves including an output plane;

(d) beam splitter means provided between said first and second liquid crystal light valves for providing selective reflection of light, the output planes of each of said first and second liquid crystal light valves directed at said beam splitter means;

(e) a light source in optical communication with said beam splitter means; and

(f) a video detector in optical communication with said beam splitter,

whereby the light produced by said light source is modulated by the light provided on the input planes of said first and second liquid crystal light valves and produces a two-dimensional cross-correlation function on said video detector.

9. An optical stereo video signal processor in accordance with claim 8 further including a peak electronic tracking means in electrical communication with said video detector for producing an electrical signal indicating the location of a peak correlation signal on said video detector.

10. An optical stereo video signal processor in accordance with claim 9 wherein said beam splitter means includes two beam splitters.

11. An optical stereo video signal processor in accordance with claim 8 further including a microprocessor for generating masks on said second display means, and a video frame memory in communication with said first video camera for storing frames generated by said first video camera to be produced on said second means, said microprocessor controlling the operation of said video frame memory.

12. An optical stereo video signal processor in accordance with claim 8 further including a video playback system and a computer, said video playback system controlled by said computer and connected to said second display means, whereby images transmitted to said second display means are optically correlated with images provided on said first display means provided by said first video camera for purposes of image identification.

13. An optical stereo video signal processor in accordance with claim 8 wherein said first and second display means directly abuts said first and second liquid crystal light valves, respectively.

14. An optical stereo video signal processor in accordance with claim 8 further including collimating lenses between said first display means and said first liquid crystal light valve, between said second display means and said second liquid crystal light valve, between said light source and said beam splitter, and between said beam splitter and said video detector.

15. An optical stereo video signal processor in accordance with claim 14 wherein said collimating lenses are convex lenses.

16. An optical stereo video signal processor in accordance with claim 14 wherein said collimating lenses are Fresnel lenses.

17. An optical stereo video signal processor comprising:

(a) a stereo camera system including first and second video cameras;

(b) first display means in communication with said first video camera and second display means in communication with said second video camera for producing an optical representation of an image detected from its respective video camera;

(c) a first charge coupled silicon device in communication with said first display means, and a second charge coupled silicon device in communication with said second display means;

(d) beam splitter means provided between said first and second charge coupled silicon devices for providing selective reflection of light;

(e) a light source in optical communication with said beam splitter; and

(f) a video detector in optical communication with said beam splitter,

whereby the light produced by said light source is modulated by said first and second charge coupled silicon devices and produces a two-dimensional cross-correlation function on said video detector.

18. An optical stereo video signal processor in accordance with claim 17 further including a peak electronic tracking means in electrical communication with said video detector for producing an electrical signal indicating the location of a peak correlation signal on said video detector.

19. An optical stereo video signal processor in accordance with claim 18 wherein said beam splitter means includes two beam splitters.

20. An optical stereo video signal processor in accordance with claim 17 further including a microprocessor for generating masks on said second display means and a video frame memory in communication with said first video camera for storing frames generated by said first video camera to be produced on said second means, said microprocessor controlling the operation of said video frame memory.

21. An optical stereo video signal processor in accordance with claim 17 further including a video playback system and a computer, said video playback system controlled by said computer and connected to said second display means, whereby images transmitted to said second display means are optically correlated with images provided on said first display means provided by said first video camera for purposes of image identification.

22. An optical stereo video signal processor in accordance with claim 17 further including collimating lenses between said light source and said beam splitter and between said beam splitter and said video detector.

23. An optical stereo video signal processor in accordance with claim 22 wherein said collimating lenses are Fresnel lenses.