US 6,256,057 B1 · Electro-optical reconnaissance system with forward motion compensation

Abstract

An electro-optical framing camera forward motion compensation (FMC) reconnaissance system comprising a moving shutter and a full frame focal plane array detector is designed to minimize the variation of image motion from a target scene across the focal plane array. The full frame focal plane array, such as a Charge Coupled Device (CCD), is designed to transfer and add the image from pixel to pixel at a predetermined rate of image motion corresponding to the region exposed by the focal plane shutter. The focal plane shutter aperture and velocity are set to predetermined values coordinated with the available illumination. The CCD image transfer rate is set to minimize the smear effects due to image motion in the region of the scene exposed by the focal plane shutter. This rate is variable with line of sight depression angle, aircraft altitude, and aircraft velocity/altitude ratio. Further, a method of FMC utilizes a comparison of a measured light level to a standard value in order to determine the appropriate exposure time and shutter motion rate. An optimal FMC clocking signal is calculated based on image motion equations incorporated in the processing unit of the reconnaissance system.

Claims32

Dependent claims

An electro-optical reconnaissance system, comprising:

a focal plane array including a main format area having a plurality of photo-sensitive cells arranged in rows and columns, wherein said focal plane array is configured to detect a projected image of a scene and to convert said image into an electronic charge representation of said image;
and
a shutter having a controllable exposure slit proximate to said focal plane array, wherein said exposure slit is moved across said focal plane array to define areas of exposure, each area of exposure having an associated image motion that is substantially uniform across said area of exposure, wherein said electronic charges representing said image are transferred at a charge transfer rate corresponding to said image motion in said associated area of exposure exposed by said shutter exposure slit, as said exposure slit is moved across said focal plane array.

An electro-optical reconnaissance system for performing forward motion compensation, wherein said reconnaissance system is installed in a vehicle capable of moving in a forward direction, comprising:

a focal plane array including a main format area having a plurality of photo-sensitive cells arranged in rows and columns, wherein said focal plane array is configured to detect a projected image of a scene and to convert said image into an electronic charge representation of said image, and wherein said focal plane array is oriented to view said scene in a forward oblique mode of operation;
and
a focal plane shutter, having a controllable exposure slit proximate to said focal plane array, wherein said exposure slit is moved across said focal plane array to define areas of exposure, each area of exposure having an associated image motion that is substantially uniform across said area of exposure, wherein said exposure slit is oriented parallel to a direction of said rows, and wherein said electronic charges representing said image are transferred at a charge transfer rate corresponding to said image motion in said associated area of exposure exposed by said shutter exposure slit, as said exposure slit is moved across said focal plane array.

An electro-optical reconnaissance system for performing forward motion compensation, wherein said reconnaissance system is installed in a vehicle capable of moving in a forward direction, comprising:

a focal plane array including a main format area having a plurality of photo-sensitive cells arranged in rows and columns, wherein said focal plane array is configured to detect a projected image of a scene and to convert said image into an electronic charge representation of said image, and wherein said focal plane array is oriented to view said scene in a side oblique mode of operation;
and
a focal plane shutter, having a controllable exposure slit proximate to said focal plane array, wherein said exposure slit is moved across said focal plane array to define areas of exposure, each area of exposure having an associated image motion that is substantially uniform across said area of exposure, wherein said exposure slit is oriented parallel to a direction of said columns, and wherein said electronic charges representing said image are transferred at a charge transfer rate corresponding to said image motion in said associated area of exposure exposed by said shutter exposure slit, as said exposure slit is moved across said focal plane array.

A method for providing forward motion compensation (FMC) for an electro-optical reconnaissance system in a vehicle capable of forward motion, said optical reconnaissance system including a moveable shutter exposure slit and a focal plane array configured to detect a projected image of a scene and to convert said image into an electronic charge representation of said image, comprising the steps of:

(1) moving the shutter exposure slit across the focal plane array to define areas of exposure, each area of exposure having an associated image motion that is substantially uniform across said area of exposure;
(2) transferring electronic charges representing the image at a charge transfer rate corresponding to said image motion in said associated area of exposure exposed by said shutter exposure slit, as said exposure slit is moved across said focal plane array;
(3) a measuring a light level of a scene to be imaged by the reconnaissance system;
(4) comparing the measured light level to a predetermined light level value;
(5) determining an exposure time by comparing the measured light level to an exposure time look-up table,
(6) determining a forward motion compensation profile corresponding to the exposure time and mission parameter inputs;
and
(7) sending a signal corresponding to said forward motion compensation profile to an electronics unit of the electro-optical reconnaissance system to perform FMC.

5 more elements

Dependencies are inferred from the claim text.

Electro-optical reconnaissance system with forward motion compensation

Life of this patent

Electro-optical reconnaissance system with forward motion compensation

Life of this patent

Abstract

Claims32