Abstract: A system is disclosed for automatically controlling the light intensity of a light source as a function of the amount of light received by a photosensor. In a preferred embodiment the light source illuminates a reference background which, in turn, reflects the light incident thereon to a photosensor in a video camera. In response to this reflected light, the photosensor produces a video signal which is proportional to the amount of light reflected thereon. A first processor is responsive to the reception of the video signal over a preselected period of time and provides a first signal which is proportional to the amount of reflected light received by the photosensor over that preselected period of time. A second processor is responsive to the first signal and generater a control signal to automatically cause an adjustable power supply to change the voltage applied to the light source as a function of the amplitude of the control signal.

Abstract: Disclosed is an automatic self-adjusting CCD activated video camera circuit for adjusting the various CCD channel offset and gain values to the desired levels by utilizing the channels' digitized internal black and white references. Two identical feedback loops are used for offset and gain adjustment, respectively. In the gain/offset adjust loop, the white/black reference is compared to a desired gain/offset set by jumpers or switches on the video camera board. A difference in these values causes a corresponding 10 bit counter to increase or decrease its value. The digital counter value is converted to an analog signal and is used to optimally modify the channel gain/offset.