US Patent 10032262 Block-based content-adaptive reshaping for high dynamic range images

A processor for signal reshaping receives an input image with an input bit depth. Block-based standard deviations are computed. The input codewords are divided into codeword bins and each bin is assigned a standard deviation value. For each bin, a standard deviation to bit-depth function is applied to the bin values to generate minimal bit depth values for each codeword bin. An output codeword mapping function is generated based on the input bit depth, a target bit depth, and the minimal bit depth values. The codeword mapping function is applied to the input image to generate an output image in the target bit depth.