Television – Image signal processing circuitry specific to television – Gray scale transformation
Patent
1996-06-14
1998-09-15
Lee, Richard
Television
Image signal processing circuitry specific to television
Gray scale transformation
382168, H04N 557
Patent
active
058086978
ABSTRACT:
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.
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Fujimura Naohiro
Hasegawa Hitoshi
Kurashita Takuji
Onishi Hiroshi
Takeuchi Shinji
Lee Richard
Mitsubishi Denki & Kabushiki Kaisha
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