Reducing artifacts in compressed images

摘要

Systems and methods of reducing artifacts in compressed images are described. In one aspect, spatially-shifted forward transforms of the input image are computed to generate respective sets of forward transform coefficients. Nonlinear transforms are applied to the forward transform coefficients of each set. Inverse transforms of the sets of nonlinearly transformed forward transform coefficients are computed to generate respective intermediate images. Respective measures of local spatial intensity variability are computed for pixels of each of the intermediate images. An output image is computed with pixel values computed based at least in part on the computed measures of local spatial intensity variability.