Leakage-Compensated, Frame-Differencing APS Imager

A proposed complementary metal oxide/semiconductor (CMOS) integrated-circuit imaging device of the active-pixel sensor (APS) type is capable of simultaneously generating the pixel-by-pixel sum and difference of two successive image frames at high speed for real-time operation, while compensating for leakage and suppressing fixed pattern noise (FPN). Frame differencing (and, to some extent, summing) is used in a variety of image-processing applications, including surveillance, range mapping, detection of motion, discrimination against background, compression of image data, and for solar-Doppler magnetographs.