A Smart Sensor for Image Processing: Towards a System on Chip

One of the solutions to reduce the computational complexity of image processing is to perform some low-level computations on the sensor focal plane. This paper presents a vision system based on a smart sensor. PARISl (programmable analog retina-like image sensor) is the first prototype used to evaluate the architecture of an on-chip vision system based on such a sensor and a digital processor. The sensor integrates analog and digital computing units. This architecture makes the vision system more compact and increases the performances reducing the data flow exchanges with the digital processor. A system has been implemented as a proof-of-concept. This has enabled us to evaluate the performance needed for a possible implementation of a digital processor on the same chip. The approach is compared to two architectures implementing CMOS sensors and interfaced to the same processor. The comparison is related to image processing computation time, processing reliability, programmability, precision, bandwidth and subsequent stages of computations