An efficient algorithm for the enhancement of JPEG-coded images

Despite its growing age, the JPEG is among the most popular choices as a standard compression scheme for continuous-tone still images. In this paper, a novel technique is proposed to alleviate the blocking artifacts that usually occur in JPEG coded images especially at low bit rates. The proposed algorithm consists of two stages: firstly, the AC coefficients are estimated based on their observed probability distribution and secondly, a postprocessing scheme is applied for blockiness removal, consisting of a region classification algorithm and a spatial adaptive filtering. Experimental results demonstrate the efficiency of the proposed method. r 2003 Elsevier Ltd. All rights reserved.