Patent ID: 8446965

Claim:
A compression noise reduction apparatus, comprising: a deblocking processing module configured to perform deblocking processing with respect to a decoded image; a peripheral pixel state determination module configured to determine a ratio of flat pixels and a ratio of edge pixels of a plurality of pixels, based on a pixel gradient of the plurality of pixels at a periphery of a filtering target pixel in the image that has been subjected to the deblocking processing at the deblocking processing module; a filter strength determination module configured to determine a filter strength such that the filter strength to be used in filter processing increases, as the ratio of the flat pixels or the ratio of the edge pixels becomes greater, in accordance with the ratio of the flat pixels and the ratio of the edge pixels; and a deringing processing module configured to determine a maximum value of pixel gradients of pixels within a predetermined range around the filtering target pixel, and to perform deringing processing using the determined filter strength by taking a value set in advance according to the maximum value as an upper limit of the filter strength.