Adaptive Gray Scale Control Circuit for Television Video Signals.

摘要

According to the patent application, television picture 'wash-out' is eliminated by means of a signal processing circuit that adapts and enhances the video gray scale of television pictures to compensate for adverse lighting conditions in the viewed area. The circuit approach comprehends processing the video signal in terms of picture area. Each step on the gray scale from black to white is assigned a percentage of the total picture. The circuit comprises a plurality of comparators each working at a different threshold level. Each comparator is followed by an integrator and a feedback circuit that adapts that comparator sense level to the incoming signal. The video signal is processed in a way that always produces certain assigned ratios of black, white, and/or shades of gray.