A NEW APPROACH TO REDUCE THE BLOCKING EFFECT OF TRANSFORM CODING

Transform coding has been successfully used for image compression in m any applications. However, it suffers from the artifact known as ''blo cking effect'' due to division of subblocks. In this paper, we propose a combined-transform coding (CTC) scheme to reduce this effect and he nce achieve better subjective performance. First the proposed CTC sche me was described and its information-theoretic properties were investi gated. Then a comparison between the CTC scheme and the DCT-based JPEG system and DWHT scheme was made to demonstrate the performance improv ement of the proposed scheme. The advantages of the proposed CTC schem e also include 1): no ringing effect due to no error propagation acros s the boundary, 2): no additional computation and 3): distortion can b e held below a certain threshold.