Tuyển tập báo cáo các nghiên cứu khoa học quốc tế ngành hóa học dành cho các bạn yêu hóa học tham khảo đề tài: Stochastic Modeling of the Spatiotemporal Wavelet Coefficients and Applications to Quality Enhancement and Error Concealment | EURASIP Journal on Applied Signal Processing 2004 12 1931-1942 2004 Hindawi Publishing Corporation Stochastic Modeling of the Spatiotemporal Wavelet Coefficients and Applications to Quality Enhancement and Error Concealment Georgia Feideropoulou Signal and Image Processing Department ENST 46 rue Barrault 75634 Paris Cedex 13 France Email feiderop@ Beatrice Pesquet-Popescu Signal and Image Processing Department ENST 46 rue Barrault 75634 Paris Cedex 13 France Email pesquet@ Received 1 September 2003 Revised 9 January 2004 We extend a stochastic model of hierarchical dependencies between wavelet coefficients of still images to the spatiotemporal decomposition of video sequences obtained by a motion-compensated 2D t wavelet decomposition. We propose new estimators for the parameters of this model which provide better statistical performances. Based on this model we deduce an optimal predictor of missing samples in the spatiotemporal wavelet domain and use it in two applications quality enhancement and error concealment of scalable video transmitted over packet networks. Simulation results show significant quality improvement achieved by this technique with different packetization strategies for a scalable video bit stream. Keywords and phrases wavelets spatiotemporal decompositions stochastic modeling hierarchical dependencies video quality scalability. 1. INTRODUCTION Video coding schemes involving motion-compensated spatiotemporal 2D t wavelet decompositions 1 2 3 have been recently shown to provide very high coding efficiency and to enable complete spatiotemporal SNR and complexity scalability 4 5 6 . Apart from the flexibility introduced by the scalability of the bit stream an increased robustness in error-prone environments is possible. Unequal error protection of such kind of bit streams is easily achievable due to the inherent priority of data. These features make scalable video methods desirable for video transmission over heterogeneous .
