Abstract
The block discrete cosine transform (DCT) is by far the most widely used transform for the compression of both still and sequences of images. However, by means of this technique, particularly for high compression ratios, so called blocking artifact arises as one of the most typical and annoying artifacts that affect images. In this paper, a method for the reduction of blocking artifact in images coded at very low bitrate is presented. We utilize maximum a posteriori (MAP) estimation and projection onto convex sets (POCS) iterative restoration to remove the blocking artifact and improve signal to noise ratio (SNR). Combined with our renovated DCT coefficient constraint, image quality improvement of 0.5〜1.6dB in terms of SNR is obtained.
