Block boundary artifact reduction for block-based image compression

摘要

Block boundary artifact reduction in decompressed digital images is accomplished by filtering the intensity of pixels in the vicinity of the block boundary. The filter utilizes filter coefficients selected from tables on the basis of the distribution of a scalar quantity describing the pixels neighboring the pixel to which the intensity adjustment is to be applied. The intensities of pixels at the boundary and one pixel removed from the boundary are adjusted. If interpolation pixels in each of neighboring blocks are of relatively constant intensity, the intensities of additional pixels, more remote from the boundary, are adjusted. Filter coefficients can be selected from different arrays for pixels on the boundary or removed from the boundary or if the pixel intensity adjustment is based on the intensities of pixels in a horizontal row or vertical column of interpolation pixels.