Image-Quality-Driven Metrics for Testing and Calibrating ADC Array in CMOS Imagers: A First Step

CMOS imagers that consist of a pixel array of image sensors, an analog-to-digital converter (ADC) array, and image signal processors (ISPs) have been widely adopted in various imaging applications. Since the array of ADCs in the imager jointly and concurrently converts the pixel data for producing a final image, their test specifications and calibration targets should consider both intra-ADC linearity and inter-ADC uniformity. In this paper, we study the case where an imager has only one ADC so as to evaluate the relationship between the ADC's static performance values and the resulting image quality. The result provides a foundation toward building effective metrics for correlating intra- and inter-ADC characteristics to the final image quality.