Pulse-based 2-D motion sensors

We present two compact CMOS integrated circuits for computing the two-dimensional (2-D) local direction of motion of an image focused directly onto the chip. These circuits incorporate onboard photoreceptors and focal plane motion processing. With fully functional 14/spl times/13 and 12/spl times/13 implementations consuming less than 50 /spl mu/W per pixel, we conclude that practical pixel resolutions of at least 64/spl times/64 are easily achievable. Measurements characterizing the elementary one-dimensional motion detectors are presented along with a discussion of 2-D performance and example 2-D motion vector fields. As an example application of the sensor, it is shown that the array as fabricated can directly compute the focus of expansion of a 2-D motion vector field.