Patent ID: 9699426
Date: 2017-07-04
CPC Classifications: G06T,H04N

Claim:
1. A method for processing a picture comprising estimating a color mapping between a first and a second color-graded version of said picture by estimating a color mapping function that maps color values of said first color-graded version of said picture onto color values of the second color-graded version of said picture, said color mapping function comprising at least two color transforms, the color values of the first color-graded version of the picture being represented in a first color volume and the color values of the second color-graded version of said picture being represented in a second color volume, wherein estimating said color mapping function comprises: a) obtaining an estimate of each color transform from the color values of said first and second color-graded version of said picture;  for the estimate of each color transform, b) obtaining an intermediate output set of color values by applying said estimate of the color transform to the color values of an input set of color values used for estimating said color transform; c) detecting whether a color value of the intermediate output set of color values exceeds a given maximal value; d) when at least one color value of the intermediate output set of color values exceeds the given maximal value, reducing the dynamic range of the color values of said intermediate output set of color values, and going back to step a).