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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: Motion Estimation and Signaling Techniques for 2D+t Scalable Video Coding | Hindawi Publishing Corporation EURASIP Journal on Applied Signal Processing Volume 2006 Article ID 57308 Pages 1-21 DOI 10.1155 ASP 2006 57308 Motion Estimation and Signaling Techniques for 2D t Scalable Video Coding M. Tagliasacchi D. Maestroni S. Tubaro and A. Sarti Dipartimento di Elettronica e Informazione Politecnico di Milano Piazza Leonardo da Vinci 32 20133 Milano Italy Received 1 March 2005 Revised 5 August 2005 Accepted 12 September 2005 We describe a fully scalable wavelet-based 2D t in-band video coding architecture. We propose new coding tools specifically designed for this framework aimed at two goals reduce the computational complexity at the encoder without sacrificing compression improve the coding efficiency especially at low bitrates. To this end we focus our attention on motion estimation and motion vector encoding. We propose a fast motion estimation algorithm that works in the wavelet domain and exploits the geometrical properties of the wavelet subbands. We show that the computational complexity grows linearly with the size of the search window yet approaching the performance of a full search strategy. We extend the proposed motion estimation algorithm to work with blocks of variable sizes in order to better capture local motion characteristics thus improving in terms of rate-distortion behavior. Given this motion field representation we propose a motion vector coding algorithm that allows to adaptively scale the motion bit budget according to the target bitrate improving the coding efficiency at low bitrates. Finally we show how to optimally scale the motion field when the sequence is decoded at reduced spatial resolution. Experimental results illustrate the advantages of each individual coding tool presented in this paper. Based on these simulations we define the best configuration of coding parameters and we compare the proposed codec with MC-EZBC a widely used reference codec implementing the t 2D framework. Copyright 2006 Hindawi .
