On Chip Error Compensation, Light Adaptation, and Image Enhancement with a CMOS Transform Image Sensor

Abstract

CMOS imagers are replacing CCD imagers in many applications and will continue to make new applications possible. CMOS imaging offers lower cost implementations on standard CMOS processes which allow for mixed signal processing on-chip. A system-on-a-chip approach offers the ability to perform complex algorithms faster, in less space, and with lower power and noise. Our transform imager is an implementation of a mixed focal plane and peripheral computation imager which allows high fill factor with high computational rates at low power. However, in order to use the technology effectively a need to verify and further understand the behavior and of the pixel elements in this transform imager was needed. This thesis presents a study of the pixel elements and mismatches and errors in the pixel array of this imager. From there, a discussion about removing offsets and an implementation of a circuit to remove the largest offsets is shown. To further enhance performance, initial work to develop light adaptive readout circuits is presented. Finally, an overview is given of a newly designed one-megapixel transform imager with many design improvements.