WAVELET AND LAPPED ORTHOGONAL-TRANSFORMS WITH OVERLAPPED MOTION-COMPENSATION FOR MULTIRESOLUTION CODING OF HDTV

To increase the robustness of high density television (HDTV) signal ag ainst transmission noise and to eliminate the ''drift'' artifacts, a m ultiresolution coding scheme for HDTV using hierarchical overlapped bl ock motion-compensated (OBMC) discrete wavelet transform and the Lappe d Orthogonal Transform (DWT-LOT) is developed. A data loss concealment scheme is required to provide graceful degradation, especially in HDT V broadcast and transmission environments. The effect of ''drift'' art ifacts is one of the major problems in a classical multiresolution vid eo coding such as frequency scalable coding where different resolution s do not have their own accurate motion information. Our research not only exploits advantages of discrete wavelet transform and hierarchica l OBMC to solve the ''drift'' problem, but also enhances MPEG scheme, which is applied for the lowest resolution, by replacing the DCT with the LOT, along with OBMC to significantly improve the data loss concea lment and mitigate the degradation of picture quality due to transmiss ion noise. Three resolutions at the constant bit rate (CBR) for applic ations to HDTV, conventional TV, and videophone are aimed at. Data los s concealment, for both intraframes and interframes, is illustrated, t he elimination of ''drift'' artifacts is demonstrated, and the superio rity of the enhanced MPEG scheme over the existing MPEG scheme is show n. Simulation results also show that good subjective and objective qua lity can be achieved for all three resolutions.