Normal optical flow measurement on CMOS APS imager

A 92×52 active pixel sensor (APS) for dense normal flow estimation is presented. The sensor combines imaging and processing on the same chip efficiently. The algorithm computes partial derivatives with respect to time and space and uses their ratio to compute normal flow velocity. The chip, which has been fabricated in a CMOS 0.5 μm process, occupies an area of 4.5 mm² and consumes 2.6 mW power at V_dd=5 V.