关键词: 块效应, 小波变换, 马尔可夫随机场, 最大后验估计

Abstract: The block-based discrete cosine transform(BDCT) has been a main compression technique in most of the international standards for image and video compression. One of the major drawbacks in BDCT is that the decoded image differs from visible blocking artifacts at low bit rates, which reduces the image visual quality. In this paper, a new deblocking algorithm based on maximum a posteriori estimation of Markov Random Field (MRF-MAP) is proposed in order to reduce blocking artifacts as many as possible, while preserving edge information. The mathematical expression is deduced to set the threshold for Huber function of MRF. The threshold obtained by this expression can provide good tradeoff between protecting image edge and improving image quality. The experiment results show the effectiveness of the proposed algorithm.

Key words: blocking artifacts, wavelet transform, Markov Random Field, maximum a posteriori estimation