an image processor system for a charge coupled device or cmos imaging system includes a histogram - based automatic gain control circuit which first controls gain by adjusting said ccd system and then for yet a higher gain level makes gain adjustments in said cdsvga circuit and a digital gain circuit to produce a combined target gain level . a processing system for an imager device includes a camera system for producing an imager signal , a correlated double sample circuit for receiving data from an imager , a variable gain amplifier , an analog - to - digital converter coupled to said cds circuit , a digital gain circuit coupled to said adc , and an automatic gain control circuit coupled to said dgc for controlling the cds circuit and the dgc , as well as shutter timing for shutter gain .