Abstract: An apparatus and method for reducing fixed pattern noise in a planar array that includes an array of image responsive detectors, a dithering mechanism for dithering an observed image relative to the array, a high pass filter, and an image restorer. The fixed pattern noise in an observed image is reduced by dithering the observed image across a plurality of detectors forming a planar array, filtering the detector responses with the high pass filter, and passing the filtered signals through the image restorer. A correcting element can be used to iteratively update the fixed pattern noise estimate. In addition, a voter or a frame averager can be included to reduce errors that might adversely effect the fixed pattern noise estimate.