In this paper

a new image decoding algorithm to remove the“blocking artifact”appearing with block-transform coding is proposed. In the algorithm

the correlation between adjacent pixels is used to define smooth constraint convex sets. At the decoder

the blocky image is projected onto these convex sets by using the theory of project onto convex sets

and the ultimate result is a smooth image without block artifact. Experiments demonstrate that this new algorithm can not only make the decoded image more smoother but also maintain the details of the image.