A Standard 3.5T CMOS Imager Including a Light Adaptive System for Integration Time Optimization
Résumé
This paper presents a light adaptive system which allows an automatic management of the integration time value of a standard 3 transistors (3T) CMOS imager. A low resolution network of high dynamic range pixels is included in this standard CMOS sensor. This low resolution network is regularly distributed on the entire photosensitive array, and computes the average light power information. This value allows the control system to choice the optimized integration time value which provides the best image quality. This imager has been designed in a 0.35 μm, 3.3 V CMOS technology. The basic photosensitive block layout contains four 3T standard pixels and one non-linear 2T pixel. Due to this distribution, we obtain a 3.5T per pixel. This sensor has been tested and TV video sequences show the efficiency of this very simple control system.