A mixed digital-analog SIMD chip tailored for image perception

A SIMD machine made of a 2D array of mixed analog-digital cells is described. Communication with the SIMD machine is tailored to be coupled both with imagers through the use of a scanner and with low level vision chips through an address bus encoding activity in pulse frequency. The digital part of a cell works on 4-bit words. A cell contains an ALU, 6 words of memory, 2 flags, a spatial analog filter connecting to the 8 neighbours to perform low or high-pass spatial filtering of the image, 9 analog multipliers for a weighted summation by a 3 by 3 kernel, an A/D converter and a D/A converter. A cell can communicate with its 8 neighbours through analog or digital links. Instructions can be masked locally allowing processing depending on local results. Each cell contains about 1040 transistors and is 235 μm by 215 μm in a 0.5 μm CMOS process