CMOS IMAGER WITH HIGH DYNAMIC RANGE

摘要

PROBLEM TO BE SOLVED: To provide an imager representing illuminance in a time region. SOLUTION: Each pixel outputs a pulse (address valid output) after a time proportional to the illuminance of the pixel once per frame. Thus, the illuminance of the pixel is related to a time difference between a pulse event and an imager global reset. A counter (171) reports the time of the pulse event in a digital form (luminance). No analog/digital converter is required in this way. The imager permits a pixel luminance histogram arithmetic operation. Frame data are stored in a memory (177) by using row and column arbiter in the order of pixel luminance and a pixel address is generated (173). Since each pixel has its own exposure time, the imager has a wide dynamic range of 120 dB. The imager indicates a low watt loss and avoids noise of the conventional complicated analog read circuit and the problem of dissidence.