A Unified Framework for Removing Blocking Artifacts

Al-Fahoum and Reza [1] characterized the blocking artifacts in block based DCT (BDCT) compressed image into five types: grid noise, staircase noise, ringing artifacts, corner outliers and the corruption of edges. Most of the comprehensive deblocking algorithms lack a unified framework, and different artifacts are processed with independent ad hoc schemes. In this paper, we propose a comprehensive postprocessing method for removing all the blocking-related artifacts in the framework of overcomplete wavelet expansion (OWE). We use the wavelet transform modulus maxima extension (WTMME) and angle extracted from the wavelet coefficients of 3-level OWE to represent the image. Both the WTMME and the angle image are reconstructed accordingly using inter-/ intra-band correlation to suppress the influence of the distortions. Simulation and comparative study have demonstrated the effectiveness of the proposed algorithm in terms of both subjective and objective quality of the resultant images.