A pipelined temporal difference imager

A 189/spl times/182 Active Pixel Sensor (APS) for temporal difference computation is presented. The temporal difference imager (TDI), fabricated in AMI 0.5 /spl mu/ process, contains in-pixel storage elements for previous and current frames. A correlated double sampling circuit is used to suppress the fixed pattern noise on both images and direct difference on the corrected images is also computed. The pixel area occupies 25 /spl mu/ by 25 /spl mu/, with fill factor of 30%. An efficient pipeline architecture for difference readout is implemented, allowing 8 bit precision of the difference imager and low temporal drop between the stored and current images. The chip consumes 30 mW at 50 fps from 5 V power supply.