High aspect stereoscopic mode camera and method

• US 6,747,686 B1
• Filed: 10/05/2001
• Issued: 06/08/2004
• Est. Priority Date: 10/05/2001
• Status: Expired due to Term

• Current Assignee: Goodrich Corporation (Rtx Corporation)
• Original Assignee: Recon/Optical, Inc. (Bourns Incorporated)
• Inventors: Bennett, Russell A.
• Primary Examiner(s): Kelley, Chris
• Assistant Examiner(s): PARSONS, CHARLES E
• Application Number:
  US09/972,262
• Time in Patent Office: 977 Days
• Field of Search: 348/144, 348/145, 348/146, 348/147, 348/46
• US Class Current: 348/145
• CPC Class Codes: G03B 35/00 Stereoscopic photography
• CPC Class Codes: H04N 13/221 using the relative movement between cameras and objects
• CPC Class Codes: H04N 13/296 Synchronisation thereof; Control thereof

Abstract

An aerial reconnaissance camera and method provides for generating a first image of the terrain of interest with the camera pointing angle oriented or rotated about an azimuthal axis some angular amount (θ1) to a first, typically forward orientation, i.e., forward of a cross-line of flight direction. An image is obtained of the ground at this orientation. Then the camera is rotated about the azimuthal axis to new angular value (θ2), which will typically be aft of the cross line of flight direction. An image is generated at this value. The camera is then rotated back to the value of θ1, and a second image in the forward orientation is generated. The camera is then rotated again to the value of θ2 and another image in the aft orientation is generated. This process of rotating the camera about the azimuthal axis and generating images in forward and aft orientations continues over and over. Eventually, as the aircraft flies past the terrain of interest, any given location in the terrain of interest will have been imaged from two different perspectives—forward and aft. The motion of the aircraft during the interim in combination with the values of θ1 and θ2 provide the high baseline for the stereo image pairs. By selection of suitable values for the angular separation of θ1 and θ2 (such as θ1=+10 degrees and θ2=−10 degrees) the result will be pairs of images of the terrain of interest having a large baseline, producing truly high aspect stereo images from a single camera. The method also works in a similar fashion by rotation back and forth about the pitch axis and imaging the terrain in forward oblique and aft oblique orientations.

Claims

1. A method of generating continuous coverage high aspect stereo images of terrain of interest on the earth from a single camera installed in a moving vehicle, comprising the steps of:

a) pointing the camera to a first camera orientation and generating an image at said first orientation;

b) changing the pointing of said camera so as to point the camera to a second camera orientation and generating an image at said second orientation, wherein said first and second orientations vary about either the pitch axis of said moving vehicle or an azimuthal axis, said first and second orientations being such that the projection of the camera field of view on the ground at said first and second orientations is substantially different with little or no overlap;

c) repeating steps a) and b) in a series of cycles as said moving vehicle moves past said terrain of interest;

d) wherein said first and second orientations are chosen such that said terrain of interest is imaged at said first and second orientations as said moving vehicle moves past said terrain of interest, the motion of said moving and the selection of said first and second camera orientations allowing said camera to generate a sequence of images which can be combined into high aspect stereo pairs of images of said terrain which provide continuous stereo coverage of said terrain and wherein said high aspect stereo images have a stereo angle greater than the field of view of the camera.

2. The method of claim 1, wherein said steps of pointing comprise the steps of rotating a pointing device for said camera about an azimuthal axis, and wherein said first orientation comprises an orientation forward of a cross-line of forward movement direction.

3. The method of claim 2, wherein said second orientation comprises an orientation aft of a cross-line of forward movement direction.

4. The method of claim 1, wherein said steps of pointing comprise the steps of rotating a pointing device for said camera about a pitch axis, wherein said first orientation comprises an orientation forward of nadir.

5. The method of claim 4, wherein said second orientation comprises an orientation aft of nadir.

6. The method of claim 1, wherein said camera operates to generate frames of imagery at said first and second camera orientations.

7. The method of claim 1, wherein said camera comprises an electro-optical camera.

8. The method of claim 1 wherein said camera comprises a multispectral or hyperspectal camera capable of imaging the terrain of interest in more than one portion of the electromagnetic spectrum at each of said first and second orientations.

9. The method of claim 6, wherein said camera operates to generate a plurality of frames of imagery across the line of flight of said moving vehicle at said first and second orientations.

10. The method of claim 1, wherein said first and second orientations vary by an amount of between 5 and 25 degrees.

11. The method of claim 1 wherein said first and second orientations remain constant during the performance of step c).

12. The method of claim 1, wherein said first and second orientations vary during the performance of step c).

13. The method of claim 1, wherein said first orientation comprises an angle θ

forward of a cross-line of forward movement direction, and wherein said second orientation comprises an angle of substantially −

θ

.

14. The method of claim 4, wherein said first orientation comprises an angle θ

forward of a nadir orientation, and wherein said second orientation comprises an angle of substantially −

θ

.

23. The method of claim 1, wherein said camera comprises a first image recording medium and a second image recording medium, said first and second image recording mediums imaging said terrain in first and second portions of the electromagnetic spectrum at each of said first and second orientations.

15. A camera for installation in a moving vehicle, comprising:

a two dimensional image recording medium;

a camera pointing device for said camera capable of changing the pointing angle of said camera about an axis; and

a control system for said camera comprising software and/or hardware operating said camera pointing device to cause said pointing device to perform the following pointing maneuvers;

1) point the camera to a first camera orientation forward of a cross-line of forward movement direction, said image recording medium generating an image at said first orientation;

2) change the pointing of said camera so as to point the camera to a second camera orientation, said image recording medium generating an image at said second orientation;

said second camera orientation at a second angular value different from said first orientation relative to the cross line of forward movement direction, wherein the projection of the field of view of the camera on the ground is substantially different in said second orientation as compared to said first camera orientation by virtue of said changing the pointing of said camera with little or no overlap, and

3) repeat steps

     1) and

     2) in a series of cycles;

wherein said first and second orientations are chosen such that a terrain of interest is imaged at said first and second orientations as said moving vehicle moves past said terrain of interest, the motion of said moving and the selection of said first and second camera orientations generating a sequence of images which can be combined into high aspect stereo pairs of images of said terrain which provide continuous coverage high aspect stereo imagery where the stereo angle is greater than the field of view of the camera.

17. The camera of claim 15 or claim 16, wherein said image recording medium comprises film.

18. The camera of claim 15 or claim 16 wherein said image recording medium comprises an electro-optical detector.

19. The camera of claim 15 or claim 16, wherein said image recording media comprises a first image recording medium imaging said terrain in a first portion of the electromagnetic spectrum and a second image recording medium imaging said terrain in a second portion of the electromagnetic spectrum.

20. The camera of claims 15 or claim 16, wherein said camera comprises a step-frame camera capable of generating overlapping frames of imagery of said terrain in the cross line of forward movement direction as said moving vehicle flies past or over the terrain of interest.

16. A camera for installation in a moving vehicle, comprising:

a two dimensional image recording medium;

a camera pointing device for said camera capable of changing the pointing angle of said camera about an axis; and

a control system for said camera comprising software and/or hardware operating said camera pointing device to cause said pointing device to perform the following pointing maneuvers;

1) point the camera to a first camera orientation forward of a nadir direction, said image recording medium generating an image at said first orientation;

2) change the pointing of said camera so as to point the camera to a second camera orientation, said image recording medium generating an image at said second orientation;

said second camera orientation at a second angular value different from said first orientation relative to nadir, wherein the projection of the field of view of the camera on the ground is substantially different in said second orientation as compared to said first camera orientation by virtue of said changing the pointing of said camera, with little or no overlap, and

3) repeat steps

     1) and

     2) in a series of cycles;

wherein said first and second orientations are chosen such that a terrain of interest is imaged at said first and second orientations as said moving vehicle moves over said terrain of interest, the motion of said moving and the selection of said first and second camera orientations generating a sequence of images which can be combined into high aspect stereo pairs of images of said terrain which provide continuous coverage high aspect stereo imagery where the stereo angle is greater than the field of view of the camera.

21. A camera for installation in a moving vehicle, comprising:

a line scanning camera;

a camera pointing device for said camera capable of changing the pointing angle of said camera about an axis; and

a control system for said camera comprising software and/or hardware operating said camera pointing device to cause said pointing device to perform the following pointing maneuvers;

1) point the camera to a first camera orientation forward of a cross-line of forward movement direction, said image recording medium generating an image at said first orientation;

2) change the pointing of said camera so as to point the camera to a second camera orientation, said image recording medium generating an image at said second orientation;

said second camera orientation at a second angular value different from said first orientation relative to the cross line of forward movement direction, wherein the projection of the camera field of view on the ground is substantially different in said second orientation as compared to said first camera orientation by virtue of said changing the pointing of said camera, and

3) repeat steps

     1) and

     2) in a series of cycles;

wherein said first and second orientations are chosen such that a terrain of interest is imaged at said first and second orientations as said moving vehicle moves past said terrain of interest, the motion of said moving and the selection of said first and second camera orientations generating a sequence of images which can be combined into high aspect stereo pairs of images of said terrain which provide continuous stereo coverage of said terrain and wherein where the high aspect stereo images have a stereo angle greater than the field of view of the camera.

22. A camera for installation in a moving vehicle, comprising:

a line scanning camera;

a camera pointing device for said camera capable of changing the pointing angle of said camera about an axis; and

a control system for said camera comprising software and/or hardware operating said camera pointing device to cause said pointing device to perform the following pointing maneuvers;

1) point the camera to a first camera orientation forward of a nadir direction, said image recording medium generating an image at said first orientation;

2) change the pointing of said camera so as to point the camera to a second camera orientation, said image recording medium generating an image at said second orientation;

said second camera orientation at a second angular value different from said first orientation relative to nadir, wherein the projection of the camera field of view on the ground is substantially different in said second orientation as compared to said first camera orientation by virtue of said changing the pointing of said camera, and

3) repeat steps

     1) and

     2) in a series of cycles;

wherein said first and second orientations are chosen such that a terrain of interest is imaged at s said first and second orientations as said moving vehicle moves over said terrain of interest, the motion of said moving and the selection of said first and second camera orientations generating a sequence of images which can be combined into high aspect stereo pairs of images of said terrain which provide continuous stereo coverage of said terrain and wherein said high aspect stereo images have a stereo angle greater than the field of view of the camera.