Patent ID: 8761249

Claim:
A method for encoding a first video image consisting of RGB pixel values having M bit each and a second video image consisting of RGB pixel values having N bit each, with M<N, wherein the first and second video image have the same spatial resolution, and wherein the first video image represents a color base layer and the second video image represents a color enhancement layer of the color base layer, comprising: generating a first transfer function having 2 N possible input values and being based on color histograms of the first and the second video image; generating a second transfer function based on the first transfer function, wherein the second transfer function has 2 M possible input values and comprises a function for mapping each of its input values to one out of 2 (N-M) corresponding values of the first transfer function; applying the second transfer function to the first video image, wherein the second transfer function is used for mapping the pixels, and wherein a transformed first video image is generated; calculating the difference between the transformed first video image and the second video image; encoding the difference; encoding the first video image; and transmitting the encoded first video image, the second transfer function and the encoded difference, wherein the generating a first transfer function comprises: generating a first color histogram of a reconstructed first image, the first color histogram having 2 M bins; generating a second color histogram of the second image, the second color histogram having 2 N bins; and generating from the first color histogram a smoothed color histogram having 2 N bins, wherein the values of each bin of the first histogram are distributed to 2 (N-M) bins, and wherein the first transfer function defines a transfer between the smoothed color histogram and the second color histogram.