A 40×40 CCD/CMOS AVD Processor for Use in a Stereo Vision System

This paper presents an analog VLSI processor chip with application in a high-speed binocular stereo vision system used for the recovery of scene depth. We have attempted to exploit the principal advantages of analog VLSI - small area, high speed, and low power - while minimizing the effects of its traditional disadvantages - limited accuracy, inflexibility, and lack of storage capacity. A CCD/CMOS stereo system implementation is proposed, capable of processing several thousand image frame pairs per second for 40×40 pixel binocular images. A 40×40 pixel absolute-value-of-difference (AVD) array, the core processor of the stereo system, was fabricated in a 2 ¿m CCD/CMOS process. Individual unit cells in the array were characterized and tested. The array functionality was next tested by imbedding it in a computurized stereo system and using both real scene and computer generated input image pairs. The system output was compared with full computer simulations for the same image pairs, showing good correlation.