Patent ID: 8207932
Filing Date: 2012-06-26
Classification: G09G

Abstract:
1. A method for determining a tonescale adjustment curve parameter, said method comprising: a) generating an image luminance histogram for an image to be displayed, said luminance histogram comprising bin values; b) weighting said histogram bin values from said image luminance histogram with distortion weight values, wherein said distortion weight values correspond to a particular source light illumination level, thereby creating weighted histogram values; c) combining said weighted histogram values to obtain distortion values for each of said source light illumination levels, said distortion values each estimating a sum of respective magnitude errors between each of a plurality of pixels' displayed values when illuminated at a respectively associated said source light illumination level and said pixels' displayed values if illuminated by a reference illumination level; d) selecting a source light illumination level for said image wherein said selecting is based on said distortion values; e) filtering said selected source light illumination level to determine a filtered source light illumination level; f) generating a tonescale adjustment curve based on said filtered source light illumination level and a strength factor; where g) said magnitude errors are calculated using the following equation: