Analysis of local light adaptation mechanism in a biologically motivated CMOS vision chip for edge detection

When designing a vision chip for edge detection, it is necessary to implement a local light adaptive-function to detect distinctive features of an image with a wide range of light intensity. Local light adaptation can achieve almost the same output level by changing the size of receptive fields of the local horizontal cell layers according to input light intensity, based on the lateral inhibitive-function of the horizontal cell. In this paper, we modeled and analyzed horizontal cells using a resistive network that consists of p-MOSFETs and verified the local light adaptation mechanism of a CMOS vision chip using the resistive network.