Patent ID: 7634150

Claim:
A method of removing ringing artifacts from a decompressed digital color image, the decompressed digital color image including a chrominance channel and a luminance channel, and further including a background and one or more foreground regions, the method comprising: performing a luminance channel processing, the luminance channel processing including: extracting a luminance channel histogram from the luminance channel; determining a background luminance value by selecting the most frequently occurring value from the luminance channel histogram as the background luminance value; computing a threshold luminance value, the threshold luminance value comprising a boundary value between background pixels of the digital image and foreground pixels of the digital image; thresholding the luminance channel based on the threshold luminance value to form a thresholded luminance channel; performing a morphological filtering on the thresholded luminance channel to form a mapped luminance channel image, the morphological filtering selected from one of a dilation process and an erosion process based on the background luminance value, to enlarge the foreground regions of the thresholded luminance channel, the enlarged foreground regions now including edge pixels of the foreground regions of the thresholded luminance channel, the background pixels of the mapped luminance channel image forming a luminance mapping of the digital image luminance channel, the luminance mapping including the background pixels of the mapped luminance channel image based on the threshold luminance value; and cleansing the background region luminance channel of the decompressed digital image based on the luminance mapping.