Mitsubishi Denki Kabushiki Kaisha

Naohiro Fujimura

Masayuki Tsuji

Shinji Takeuchi

Hiroshi Onishi

Takuji Kurashita

Hitoshi Hasegawa

Yuuji Yamamoto

A video contrast enhancer enhances luminance contrast by dividing each video frame or field into blocks, calculating a mean luminance level for each block, selecting mapping functions on the basis of these mean luminance levels over a series of frames or fields, and mapping the video luminance levels according to the selected mapping functions. Color-saturation contrast is enhanced by modifying the amplitude of the modulated chrominance signal by the histogram equalization method, preferably by making a single linear modification in each period of the chrominance signal, so that color phase is not affected. For video signals with non-picture bands, these enhancements are preferably restricted to the picture area. If a black offset is present, it is preferably removed.

Growing community of inventors

Tokyo, Japan

Naohiro Fujimura