Automatic channel gain and offset balance for video cameras employing multi-channel sensors

Claim 1

Imaging apparatus comprising: a multi-channel area sensor which produces 1-n parallel analog image signals representative of a sensed image, where n is a whole number; 1-n parallel image processing channels for respectively processing said 1-n parallel analog image signals; each of said image processing channels including (a) an analog-to-digital converter (ADC) for converting said analog image signal to a digital image signal, wherein each said ADC has a fine gain parameter which is a function of a top ladder potential and also has a fine offset parameter which is a function of a bottom ladder potential; and (b) a video amplifier coupled between said area sensor and said ADC, wherein each said video amplifier has coarse gain and coarse offset parameters; a serial input-output loop serially connecting each of said 1-n ADCs and each of said 1-n video amplifiers; and a control for sending digital fine gain, fine offset control signals over said serial input-output loop to control the fine gain and fine offset of each of said 1-n ADCs and digital coarse gain and coarse offset signals over said serial input-output loop to control the coarse gain and coarse output of each of said 1-n video amplifiers in order to produce a combined digital image signal having a uniform tonal range over the entire image when reproduced in a visual form.