Video compression can reduce the amount of data information in multimedia sensor networks. Traditional distributed video coding scheme that adopts regional unified coding may induce the distortion problem in decoding estimation of the intense motion region. This paper proposes an improved algorithm for DVC. The algorithm is based on image gradient field. The regions of the Wyner-Ziv frame that cannot be coded or decoded accurately are extracted according to the criteria of ROI and compressed with entropy coding. Other regions are encoded and decoded based on LDPC. The optimization of video transmission is achieved eventually. Simulation results show that; the proposed algorithm can enhance the encoding efficiency of the intense motion region; the algorithm can also reduce the rate and improve the quality of decoded image, and decrease the energy consumption of sensor nodes ultimately.%视频压缩可以降低多媒体传感器网络中的数据信息量.传统分布式视频编码方案采用区域统一编码,可能导致运动剧烈区域解码估计的失真.提出一种改进的分布式视频编码算法.该算法基于图像梯度场,针对Wyner-Ziv帧不能准确编解码的区域,通过ROI判定准则提取该区域并基于熵编码压缩,图像其他区域则基于LDPC实现分布式编解码,进而实现视频的优化传输.仿真实验表明:本文算法可增强运动剧烈区域的编码效率,在降低码率的同时提高解码图像质量,最终降低传感器节点能耗.
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