Blocking Artifact Reduction in Compressed Data

One of the major drawbacks of the block-based DCT compression methods is the introduction of blocking artifacts, which represent the artificial discontinuity between adjacent blocks. Blocking artifacts results because of independent processing of the blocks without taking into account the inter block pixel correlation. Under very high compression ratios, annoying artifacts known as blocking artifacts are more prominent. This paper proposes a new adaptive post-filtering algorithm to remove coding artifacts in block-based DCT compressed medical images. The blocking artifact in the smooth and non-smooth regions are removed by modifying a few DCT coefficients while an edge preserving smoothing filter is applied to the intermediate region. Experimental results illustrating the performance of proposed method on the basis of PSNR, MSSIM indices are presented and evaluated. Compared with other methods, the proposed one achieves better detail preservation and artifact removal performance with lower computational complexity.