Non-uniformity correction in a multielement detector array

Abstract

Disclosed is a multielement staring infrared imaging system, including a focal plane array of detectors for responding to a scene, a CCD multiplexer for serializing the outputs of the detectors, a CCD driver for controlling the multiplexer, an analog to digital converter for digitizing the serialized outputs, a recursive filter for weighting the digitized outputs and combining the weighted outputs with previous weighted outputs to produce a correction output, an arithmetic unit for subtracting the correction output from the digitized output to compensate for the non-uniformity of each detector, a waveform generator for synchronizing the operation of the CCD driver, the analog to digital converter, and the offset correction unit, and an imager display for receiving the compensated output and displaying a corrected image of the scene. Non-uniformities in the elements of an infrared staring detector array are corrected by the steps of recording the outputs of the array at each readout time, element by element, combining the outputs recorded during a selected time interval, element by element, in a convolution integral to produce an averaged background response for each element, and subtracting the averaged response for each element from the most recent response for that element to correct for the non-uniformity of that element.