摘要 |
A method for improvement of contrast in an image shown on a display having a range of displayable video levels. The method comprises providing input video levels representing the image, said levels being within said displayable range; providing a transfer function ( 120, 121 ) having a slope greater than one everywhere in a gain region ( 130 ) of said displayable range, and a slope greater than zero and less than one everywhere in a softclip region ( 131 ) of said displayable range, said regions ( 130, 131 ) meeting at a threshold level ( 125 ), the transfer function ( 120, 121 ) being adapted to transfer any input video level within said displayable range to an output level within displayable said range; and transforming said input levels into output levels within said range, using the transfer function ( 120, 121 ). According to the invention, instead of "hardclipping" there is a "softclipping" of levels. Hence, compared to conventional methods, a higher gain may be used. In practical situations, the gain applied in the gain region typically may be up to 4.
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