Multi-chip neuromorphic motion processing

We describe a multi-chip CMOS VLSI visual motion processing system which combines analog circuitry with an asynchronous digital interchip communications protocol to allow more complex motion processing than is possible with all the circuitry in the focal plane. The two basic VLSI building blocks are a sender chip which incorporates a 2D imager array and transmits the position of moving spatial edges, and a receiver chip which computes a 2D optical flow vector field from the edge information. The elementary two-chip motion processing system consisting of a single sender and receiver is first characterized. Subsequently, two three-chip motion processing systems are described. The first such system uses two sender chips to compute the presence of motion only at a particular stereoscopic disparity. The second such system uses two receivers to simultaneously compute a linear and polar topographic mapping of the image plane, resulting in information about image translation, rotation, and expansion. These three-chip systems demonstrate the modularity and flexibility of the multi-chip neuromorphic approach.