A single-chip optical sensor with analog memory for motion detection

A 64/spl times/64-pixel image sensor with full-frame analog memory and on-chip motion processor is presented. The processor consists of a charge amplifier and an analog subtractor. It uses the switched-capacitor technique and calculates the difference between the values of the signal on each pixel in successive frames. The rate can achieve up to 60 frames/s with limited area and power overhead. The analog memory required for the storage of the previous frame is implemented using implanted capacitors placed within the sensor array. Fabricated in a 1.2-/spl mu/m standard CMOS process with an added metal 3 light-shielding layer, the circuit is fully functional and requires a total core area of 13 mm/sup 2/.>