Algebraic scene-based nonuniformity correction in focal plane arrays

An algorithm is developed to compensate for the spatial fixed-pattern (nonuniformity) noise in focal-plane arrays, which is a pressing problem, particularly for mid- to far- infrared imaging systems. The proposed algorithm uses pairs of frames from an image sequence exhibiting pure horizontal and vertical sub-pixel shifts. The algorithm assumes a linear irradiance-voltage model for which the nonuniformity is attributed only to variation in the offset of various detectors in the array. Using a modified gradient-based shift estimator, pairs of frames exhibiting the above shift requirements can be identified and used to generate a correction matrix, which will compensate for the offset nonuniformity in all frames. The efficacy of this nonuniformity correction technique is demonstrated by applying it to infrared and simulated data. The strength of this technique is in its simplicity, requiring relatively few frames to generate an acceptable correction matrix.