A Biologically Inspired CMOS Image Sensor for Polarization and Fast Motion Detection

A CMOS image sensor replicating the perception of vision in insects is presented for machine vision applications. The image sensor can sense polarization information in real time using a metallic wire grid micro polarizer. The embedded polarizer uses the inherent property of materials to partially polarize the reflected light to classify among conductive materials. The sensor is also equipped with in-pixel analog and digital memories which allow in-pixel binarization in real time. The binary output of the pixel tries to replicate the "flickering effect" of the insect's eye to detect the smallest possible motion based on the change in state of each pixel. A built-in counter counts the changes in states for each row to estimate the direction of the motion. The image sensor consists of an array of 128x128 pixels, occupies an area of 5x4mm(2) and it has been designed and fabricated in a 180nm CMOS process.