REMOVAL OF COMPRESSION ARTIFACTS USING PROJECTIONS ONTO CONVEX-SETS AND LINE PROCESS MODELING

In this Paper,,ve present a new image recovery algorithm to remove,in addition to blocking, ringing artifacts from compressed images and vid eo. This new algorithm is based on the theory of projections onto conv ex sells (POCS). A new family of directional smoothness constraint set s is defined based on line processes modeling of the image edge struct ure. The definition of these smoothness, sets also takes into account the fact that the visibility of compression artifacts in an image is s patially varying. To overcome the numerical difficulty in computing th e projections onto these sets, a divide-and-conquer (DAC) strategy is introduced. According to this strategy, new smoothness sets are derive d such that their projections are easier to compute. The effectiveness of the proposed algorithm is demonstrated through numerical experimen ts using Motion Picture Expert Group based (MPEG-based) coders-decoder s (codecs).