New adaptive postprocessing to remove blocking artifacts for DCT coded image

Abstract

To remove blocking artifacts, this paper proposes a novel adaptive postprocessing method in Block-based Discrete Cosine Transform (BDCT) coded images and presents a framework, which is a serial-concatenation of a simple deblocking filter and a constraint set based on the POCS algorithm. At first, we classify the simple deblocking filter by an adaptive threshold depending on local statistical properties, and in the meantime, update block types appropriately by a simple rule, which affects the performance of deblocking progresses decisively. Secondly, a quantization constraint set (QCS) based on the projection onto convex sets (POCS) algorithm is introduced. At last, comprehensive experiments indicate that the proposed algorithm outperforms a large number of deblocking methods in the literature, in terms of evaluation of PSNR and subjective visual qualities.