Pixel-Summing APS Imager With Differential Column Readout

A complementary metal oxide/semiconductor (CMOS) integrated-circuit video image detector of the active-pixel-sensor (APS) type has been designed to implement programmable multiresolution output (through summing of outputs from selected groups of neighboring pixels) in a low-power, high-speed, low-noise differential column-readout scheme. This scheme increases (relative to CMOS APS devices of older designs) the signal-to-noise ratios achievable under low illumination.