An 8-stage time delay integration CMOS image sensor with on-chip polarization pixels

Abstract

Machine vision applications involving the assistance of robots for scene mapping or object classification encounter issues when faced with smooth transparent surfaces, such as glass. Specular reflection from such surfaces saturate the image sensor pixels, restricting their vision of objects beyond the surface. The problem is aggravated by the movement of the robot, making traditional approaches unfeasible. We propose a solution that uses on-chip polarizers to limit the specular reflection and improve scene visibility while overcoming the limited SNR and motion artifacts by using a time delay integration image sensor. We have fabricated a 256×8×5 prototype sensor using a 0.18μm CIS process which achieves a DR of 52.3dB while providing an SNR improvement of 8.8dB over a single-stage linear scanner.