| 摘要 |
PROBLEM TO BE SOLVED: To provide a gradation correction device capable of executing optimum gradation correction corresponding to the degree of deviation of a brightness distribution of an image by preventing excessive extension in the range of a dynamic range of the brightness distribution. SOLUTION: Correction brightness levels in each of plural brightness levels are formed based on frequency data of a brightness distribution so that the brightness distribution of an input brightness signal is extended to the range of a prescribed dynamic range, and memorized in a maximum correction table memory 13. A variance value of the brightness distribution is calculated corresponding to the frequency data, and a mixing ratio is set based on the variance value. The brightness levels and the correction brightness levels in the maximum correction table memory 13 corresponding thereto are mixed with the mixing ratio in each of the plural brightness levels. The mixed levels are memorized in a lookup table memory 20 as table data corresponding to each of the plural brightness levels. The level data corresponding to the brightness level of the input brightness signal is read out from the lookup table memory 20 and outputted as a gradation correction brightness signal.
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