| 摘要 |
PROBLEM TO BE SOLVED: To ensure color reproductivity when improving the tonality of a low tone image. SOLUTION: The RGB values of each pixel in every frame are converted into ideal tristimulus values X, Y, and Z. Based on a chromaticity-histogram based on the tristimulus values X, Y, and Z and a color reproduction area for each Y value corrected in accordance with a backlight-brightness, an xy error count generation part 80 obtains the number of chromaticity errors for each of a plurality of backlight-brightnesses. A lightness-histogram is created based on the RGB signals for each frame. Based on the histogram and a lightness which becomes higher than a maximum tone after being corrected according to the backlight-brightness, a lightness error count generation part 120 obtains the number of lightness errors for each of the plurality of backlight-brightnesses. An error minimum BL-brightness detection part 160 determines an optimum backlight-brightness based on the number of chromaticity errors and the number of lightness errors. A tone conversion part 170 performs tone conversion in accordance with the backlight-brightness. COPYRIGHT: (C)2010,JPO&INPIT
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