Real-Time Analog VLSI Sensors for 2-D Direction of Motion

Optical flow fields are a primary source of information about the visual scene in technical and biological systems. In a step towards a system for real time scene analysis we have developed two new algorithms for the parallel computation of the direction of motion field in 2-D. We have successfully implemented these algorithms in analog VLSI hardware such that all processing is performed in the focal plane of the imager. We present data from 12 × 13 and 15 × 14 test arrays and show that the sensors are reliable for over one order of magnitude in velocity and down to 20% contrast. The algorithms allow for a very small pixel size (110μm × 110μm in a 1.2μm CMOS process) and thus high resolution arrays are feasible.