High resolution long-range camera for an airborne platform

• US 5,625,409 A
• Filed: 08/16/1995
• Issued: 04/29/1997
• Est. Priority Date: 10/14/1992
• Status: Expired due to Fees

• Current Assignee: Matra Cap Systemes
• Original Assignee: Matra Cap Systemes
• Inventors: Rosier, Jean-Claude, Bretaudeau, Francis
• Primary Examiner(s): GARBER, WENDY RAE
• Application Number:
  US08/515,496
• Time in Patent Office: 622 Days
• Field of Search: 348/117, 348/218, 348/144, 348/145, 348/146, 348/147, 348/215, 348/216, 348/217, 348/317
• US Class Current: 348/117
• CPC Class Codes: G01C 11/02 Picture taking arrangements specially adapted for photogrammetry or photographic surveying, e.g. controlling overlapping of pictures
• CPC Class Codes: G01C 11/025 by scanning the object

Abstract

A camera device comprises a first detector having opto-electronic sensors for enabling an entire image to be input simultaneously, and associated with an optical system of long focal length. A second detector is associated with an optical system that gives a large field of view, covering the field of the first detector and extending beyond it. The camera device also includes means for synchronizing the images taken by the two detectors and for recording them.

Claims

1. A camera device for use on an airborne platform to provide recordable high-resolution images of a scene in the form of a strip that is elongated in a travel direction of the platform, said camera device comprising:

first detector means arranged for being securely connected on the platform, including a first detector having a two dimensional matrix of opto-electronic sensors and a first optical system of long focal length forming an image of a zone of said scene on said first detector which is arranged to acquire all points of said image simultaneously and to deliver a signal representing said image as a full frame on an output thereof;

second detector means arranged for being securely connected to the platform, including a second detector having a two dimensional matrix of opto-electronic sensors and a second optical system, having a short focal length as compared with the focal length of said first optical system, forming an image on said second detector which is arranged to deliver a signal representing the image formed on said second detector;

means for synchronizing times at which images are simultaneous taken by the two detector means and for recording the signals representing the images, said times being sufficiently close to each other for two successive images from said first detector means to overlap mutually;

optical scanning means optically associated with said first detector means for scanning transversely to said travel direction, arranged for directing a field of view of said first detector means into a plurality of successive directions for scanning transversely to said travel direction, said successive directions being such that different zones of the scene each in the field of view of said first detector in a respective one of said successive directions overlap partially and are all within the field of view of said second detector; and

image processing means for mutually repositioning said images formed by said first detector means and providing a two dimensional mosaic of images.

2. A camera device according to claim 1, wherein each of said first and second detectors includes a matrix of charged-coupled sensors having an integration time selected as a function of the speed of the platform so that streaking and transverse movements due to motion of the platform during integration remain compatible with a desired definition.

3. A camera device according to claim 2, wherein each of the first and second detectors is associated with means for transferring each image generated by the respective detector as a full frame to a recorder in the form of two interlaced fields.

4. A camera device according to claim 1, wherein said first detector means has a light intensifier placed between said long focal length optical system and said first detector.

5. A camera device according to claim 4, wherein said light intensifier is energized by pulsed high voltage for generating short exposure times and constituting a shutter.

6. A camera device according to claim 1, wherein the intensifier has proximity focussing and has an output coupled to a bundle of optical fibers.

9. A camera device according to claim 1, wherein the first detector includes a matrix of sensors disposed in rows and columns and the first detector means further comprises a plurality of light guides forming images of different ground parcels on zones each constituted by only some of the rows of the matrix, said different ground parcels being offset laterally relative to one another.

7. A camera device for use on an airborne platform to provide recordable high-resolution images of a scene in the form of a strip that is elongate in a travel direction of the platform, said camera device comprising:

first detector means arranged for being securely connected on the platform, including a first detector having a matrix of opto-electronic sensors and a first optical system of long focal length forming an image of a zone of said scene on said first detector which is arranged to deliver a signal representing said image as a full frame on an output thereof; and

a light intensifier placed between said long focal length optical system and said first detector, energized by high voltage pulses;

second detector means arranged for being securely connected on the platform, including a second detector having a matrix of opto-electronic sensors and a second optical system, having a short focal length as compared with the focal length of said first optical system, forming an image on said second detector which is arranged to deliver a signal representing the image formed on said second detector; and

means for synchronizing the times at which images are taken by the two detector means and for recording the signals representing the images;

wherein said first detector includes a matrix of sensors disposed in rows and columns and said first detector means further comprises a plurality of light guides forming images of different ground parcels on zones of said first detector each constituted by only some of the rows of the matrix, said different ground parcels being offset laterally relative to one another and all being within the field of view of said second detector.

8. A camera device for use on an airborne platform to provide recordable high-resolution images of a scene in the form of a strip that is elongate in a travel direction of the platform, said camera device comprising:

first detector means arranged for being securely connected to the platform, including a first detector having a two dimensional matrix of opto-electronic sensors disposed in rows and columns and a first optical system of long focal length forming an image of a zone of said scene on said first detector which is arranged to acquire all points of said image simultaneously and to deliver a signal representing said image as a full frame on an output thereof;

a light intensifier placed between said long focal length optical system and said first detector; and

means for periodically energizing said light intensifier by high voltage pulses of short duration, whereby said light intensifier constitutes a shutter of said first detector means;

second detector means arranged for being securely connected on a platform, including a second detector having a two dimensional matrix of opto-electronic sensors and a second optical system, having a short focal length as compared with the focal length of said first optical system, forming an image on said second detector which is arranged to deliver a signal representing the image formed on said second detector, said second optical system having a field of view that includes said zone and overlaps the field of view of said first detector means; and

means for synchronizing times at which images are taken by the detector means and for recording the signals representing the images, said times being sufficiently close to each other for two successive images from said first detector means to overlap mutually; and

image processing means for mutually repositioning said images formed by said detector means by correlation with said images provided by the second detector means at the same time and providing a mosaic of said images formed by said first detector means.

10. A camera device according to claim 8, wherein said light guides are optical fibers distributed in sheets, said sheets being curved or disposed obliquely relative to one another, end faces of said oblique sheets being machined so as to lie in a common plane parallel to the plane of the matrix.

11. A camera device for use on an airborne platform to provide recordable high-resolution images of a scene in the form of a strip that is elongate in a travel direction of the platform, said camera device comprising:

first detector means arranged for being securely connected to the platform, including;

a first detector having a two dimensional matrix of opto-electronic sensors disposed in rows and columns and a first optical system of long focal length forming an image of a zone of said scene on said first detector which is arranged to acquire all points of said image simultaneously and to deliver a signal representing said image as a full frame on an output thereof; and

a plurality of light guides located for forming individual images of different ground parcels which together constitute said zone, each said individual image being formed on only some of the rows of the matrix, said different ground parcels being mutually offset relative to one another laterally with respect to said travel direction;

second detector means arranged for being securely connected on a platform, including a second detector having a two dimensional matrix of opto-electronic sensors and a second optical system, having a short focal length as compared with the focal length of said first optical system, forming an image on said second detector which is arranged to deliver a signal representing the image formed on said second detector, said second optical system having a field of view that includes said zone and overlaps the field of view of said first detector means; and

means for synchronizing times at which images are simultaneous taken by the two detector means and for recording the signals representing the images, said times being sufficiently close to each other for two successive images from said first detector means to overlap mutually.

12. A camera device according to claim 11, wherein said light guides are arranged so that said different ground parcels seen by said first detector means are mutually staggered in the travel direction.

13. A method of taking pictures from air carrier, for providing recorded high-resolution images of a whole scene in the form of a strip that is elongate in a direction of travel of the carrier, comprising the steps of:

taking successive images along the strip with a first detector which is secured to the carrier and includes a two dimensional matrix of electro-optical sensors, each image being simultaneously acquired by all said electro-optical sensors as a full frame and said first detector having an optical system of long focal length, said successive images being taken at a rate sufficient for two successive images to have an overlap in the direction of travel, and for each point of said scene to appear on a plurality of said successive images;

recording the successive images delivered by the first detector;

taking successive images with a second detector also secured to the carrier, having an optical system providing a field of view greater than that of the first detector, including the field of view of the first detector and overlapping said field of view of the first detector, said second detector being synchronized with the first detector;

recording the successive images delivered by the second detector;

mutually matching the successive recorded images obtained with the first detector by correlating them with the recorded images provided by the second detector; and

mutually repositioning the successive recorded images obtained with the first recorder for providing a mosaic of images.