White balance adjusting device of color video camera

Abstract

A white balance adjusting device detects a change of color temperature for an illuminating light source from chrominance signals supplied from an image pickup device of a color video camera and controls gains of circuits of a chrominance signal processing circuit for processing red (R) signal and blue (B) signal in accordance with the detected signal to automatically adjust the white balance. The device has a circuit for generating a color temperature change detection signal from at least two different chrominance signals, a comparator/amplifier for amplifying a difference between the detection signal and a reference voltage, a tracking correction circuit to which the output of the comparator/amplifier is supplied and which produces two control signals, and gain control circuits for controlling gains for the red (R) signal and blue (B) signal in accordance with the two control signals. The color temperature change detection circuit, comparator/amplifier, tracking correction circuit and gain control circuits constitute a negative feedback loop.

Dependencies are inferred from the claim text.