Method and apparatus for post-processing images

A method for transmitting images including the receipt of an encoded image, the decoding of said image and the post-processing of said decoded image, said image signals comprised of blocks including blocks having mosquito noise artifacts, said blocks comprised of pixels including edge pixels and non-edge pixels, said edge pixels containing true edge pixels and false edge pixels, said post-processing comprising the steps of:

• identifying said edge pixels;
• distinguishing said edge pixels between said true edge pixels and said false edge pixels, said distinguishing step including comparing said pixels with at least one adjacent pixel whereby a degree of connectivity is established and determining said true edge pixels based on said degree of connectivity of said pixels;
• generating a map based on said distinguishing step;
• smoothing said false edge pixels based on said generated edge map;
• and
• filtering the pixels not identified as edge pixels.

A method for transmitting images including the receipt of an encoded image, the decoding of said image and the post-processing of said decoded image, said image signals comprised of blocks including blocks having mosquito noise artifacts, said blocks comprised of pixels including true edge pixels and false edge pixels, said edge pixels containing true edge pixels and false edge pixels, said post-processing comprising the steps of:

• distinguishing said edge pixels between said true edge pixels and said false edge pixels, said distinguishing step including comparing said edge pixels with at least one adjacent pixel whereby a degree of connectivity is established and determining said true edge pixels based on said degree of connectivity of said edge pixels;
• generating a map based on said distinguishing step;
• smoothing said false edge pixels based on said generated edge map;
• and
• filtering said image signals based on said detected true edge pixels.

A system for transmitting images including the receipt of an encoded image, the decoding of said image and the post-processing of said decoded image, said image signals comprised of blocks including blocks having blocking effect artifacts and blocks having mosquito noise artifacts, said blocks comprised of pixels including edge pixels and non-edge pixels wherein said edge pixels include true edge pixels and false edge pixels, said system comprising:

• a first post-processing coder for reducing said blocking effect artifacts from said blocks, said first post-processing including
• a DCT domain detector for detecting blocks having said blocking effect artifacts and for generating a block map including detected blocks having said blocking effect artifacts and blocks not having said blocking effect artifacts, and
• a filter for smoothing the edges of said detected blocks based on the blocks adjacent thereto according to said generated block map;
• and
• a second post-processing coder for reducing said mosquito noise artifacts from said blocks, said second post-processing coder including a detector for identifying said edge pixels and a filter for smoothing the pixels not identified as said edge pixels by said edge pixel detector, said edge pixel detector being capable of distinguishing between said true edge pixels and said false edge pixels and including a filter for smoothing said false edges whereby said false edges are smoothed into non-edge pixels.