A single-chip 10000 frames/s CMOS sensor with in-situ 2D programmable image processing

Abstract

A high speed Analog VLSI Image acquisition and pre-processing system is described in this paper. A 64times64 pixel retina is used to extract the magnitude and direction of spatial gradients from images. So, the sensor implements some low-level image processing in a massively parallel strategy in each pixel of the sensor. Spatial gradients, various convolutions as Sobel Alter or Laplacian are described and implemented on the circuit. The retina implements in a massively parallel way, at pixel level, some various treatments based on a four-quadrants multipliers architecture. Each pixel includes a photodiode, an amplifier, two storage capacitors and an analog arithmetic unit. A maximal output frame rate of about 10000 frames per second with only image acquisition and 2000 to 5000 frames per second with image processing is achieved in a 0.35 mum standard CMOS process. The retina provides address-event coded output on three asynchronous buses, one output is dedicated to the gradient and both other to the pixel values. A prototype based on this principle, has been designed. Simulation results from Mentor Graphicstradesoftware and AustriaMicrosystem design kit are presented.