BRIGHTNESS SIGNAL PROCESSING APPARATUS AND BRIGHTNESS SIGNAL PROCESSING METHOD

摘要

[PROBLEMS] To improve accuracy of determining the average brightness level and maximum and minimum levels of the brightness signals for the entire screen. [MEANS FOR SOLVING PROBLEMS] There are included a differentiating circuit that detects and differentiates rising or falling edges in horizontal and vertical sync signals of an input image signal, thereby outputting horizontal and vertical differentiated signals synchronized with the horizontal and vertical sync signals, respectively; a sample window circuit that detects the beginning and ending positions of horizontal and vertical intervals to produce sample window signals established in any desired vertical and horizontal positions on the screen in accordance with the horizontal and vertical differentiated signals; and a brightness signal output circuit that outputs sampled brightness signals when the sample window circuit is operative.