Dual band framing reconnaissance camera

A framing aerial reconnaissance camera for installation in an aerial reconnaissance vehicle, comprising;

• (a) an optical system incorporated into a camera housing, comprising:
• (1) an objective optical subassembly receiving incident radiation from a scene external of said vehicle;
• (2) an optical channel receiving radiation from said objective optical subassembly, and
• (3) a two-dimensional image recording medium in said optical channel for generating frames of imagery in a band of the electromagnetic spectrum, said optical channel including one or more optical elements focusing radiation from said scene on said two-dimensional image recording medium;
• (b) a first motor system coupled to said camera housing rotating said camera about a first axis, said camera housing installed in said aerial reconnaissance vehicle such that said first axis of rotation is parallel to the roll axis of said aerial reconnaissance vehicle,
• wherein said image recording medium is exposed to said scene to generate frames of imagery as said first motor system rotates said camera in a continuous fashion about said first axis, said image recording medium having a means for compensating for image motion due to said rotation of said camera housing;
• and
• (c) a second motor system coupled to said objective optical subassembly, said second motor system rotating said objective optical subassembly about a second axis in the direction of forward motion of said vehicle about an axis to compensate for forward motion of said aerial reconnaissance vehicle.

A framing aerial reconnaissance camera for installation in an aerial reconnaissance vehicle, comprising;

• (a) an optical system incorporated into a camera housing, comprising:
• (1) a Cassegrain optical system for receiving incident radiation from a scene external of said vehicle;
• (2) an optical channel receiving radiation from said Cassegrain optical system, and
• (3) a two-dimensional electro-optical detector in said optical channel for generating frames of imagery in a band of the electromagnetic spectrum, said optical channel including one or more optical elements focusing radiation from said scene on said two-dimensional electro-optical detector;
• (b) a first motor system coupled to said camera housing rotating said camera about a first axis, said camera housing installed in said aerial reconnaissance vehicle such that said first axis of rotation is parallel to the roll axis of said aerial reconnaissance vehicle,
• wherein said detector is exposed to said scene to generate frames of imagery as said first motor system rotates said camera in a continuous fashion about said first axis, and
• (c) a second motor system coupled to said Cassegrain optical system, said second motor system rotating said Cassegrain optical system about a second axis in the direction of forward motion of said vehicle about an axis to compensate for forward motion of said aerial reconnaissance vehicle,
• wherein said electro-optical detector comprises an array of pixel elements arranged in a plurality of rows and columns, and wherein said detector further comprises electronic circuitry coupled to said array transferring pixel information in array from row to adjacent row at a pixel information transfer rate substantially equal to the rate of image motion in the plane of said electro-optical detectors due to roll of said camera;
• said electronic circuitry and said second motor system operative to achieve roll motion compensation and forward motion compensation simultaneously in said array to thereby enable high resolution images to be obtained from said electro-optical detector.

A method of generating frames of imagery of a scene of interest with an aerial reconnaissance camera in two different bands of the electromagnetic spectrum simultaneously, comprising the steps of:

• providing two photosensitive electro-optical detectors in said camera, each of said detectors comprising an array of pixel elements arranged in a plurality of rows and columns;
• rotating said camera in a continuous fashion about a roll axis either coincident with or parallel to a roll axis of an aerial reconnaissance vehicle carrying said camera;
• while rotating said camera, simultaneously exposing said electro-optical detectors to a scene of interest in a series of exposures;
• while rotating said camera and while exposing said electro-optical detectors to said scene, rotating an optical system providing an objective lens for said camera in the direction of forward motion of said vehicle at a predetermined rate to cancel out image motion due to forward motion of said vehicle;
• and
• while said electro-optical detectors are being exposed to said scene, moving pixel information in said arrays at a rate and in a direction substantially equal to the rate of image motion due to rotation of said camera about said roll axis to thereby preserve resolution of an image generated by said detectors.