A 66 × 66 pixels analog edge detection array with digital readout

Edge detection is a common first step in artificial vision systems. Usually this task is performed by computation on digitized data from an analog CCD or CMOS camera. This paper describes an analog approach to edge detection using a kind of resistive fuse algorithm. 66 × 66 pixels are interconnected with their nearest neighbors by a novel combination of switched capacitor resistors and comparators. The chip accepts analog input up to 10 MHz and delivers digital edge data with an internal data rate of 550 Mbyte/s. The typical processing time for one frame is only 2µs. An integrated digital sequencer with static program memory allows versatile control of the algorithm. The presented chip is especially suited for integration as an analog front end in larger systems, preferable on a single die. It eliminates the need for an analog to digital converter and its high output data rate and programmability make it possible to look at the same image under different aspects more than once.