Abstract:

In the compression system based on DCT(Discrete Cosine Transform),the DCT is based on the block.Images are first broken down into 8×8 pixels pieces,then it gets 64 DCT coefficients through DCT for each block.Since each block gets DCT respectively,the correlation between blocks are ignored,thus the "Blocking Effects".This paper proposes an improved method for reducing blocking effect based on post-processing.When the images are reconstructed,four modes are proposed for the corner of four blocks,including three frequency-related modes (smooth mode,non-smooth mode,and intermediate mode) and a corner mode.A low computational deblocking filter is then adopted for different mode,and images are reconstructed.Both visual effect and image quality are improved.

Key words: DCT;blocking effects;post-processing