For each of a plurality of homogeneity regions in relative pixel space, a deviation associated therewith with respect to a pixel to be filtered is given by a sum of associated difference values, each difference value given by the absolute value of a difference between a value of a pixel to be filtered and that of a neighboring pixel selected in accordance with the selected homogeneity region. The filtered pixel value is responsive to values of the neighboring pixels for the homogeneity region with minimum deviation. The relative pixel locations of each homogeneity region are symmetric relative to a radially-extending axis extending outwards in a corresponding polar direction therealong from a relatively central pixel location to a boundary of the homogeneity region, including all relative pixels intersected by the radially-extending axis, different homogeneity regions being associated with different polar directions.