| Compared to traditional wireless sensor networks, wireless multimedia sensor networks can provide richer video information in environmental monitoring. In recent years more attention has been paid to WMSNs. However, because sensor node is a node composed of a variety of media types, network heterogeneity lead to bandwidth frequent fluctuation in WMSNs. The sensor node mobility leads to changes of network topology. At the same time, there is limited bandwidth and energy, etc. problem, which all bring challenges to the video data transmission. To solve these problems, people began to research into Fine Granularity Scalability coding techniques and multi-path transmission technology.Firstly, this paper research Fine Granularity Scalability FGS coding technology. A FGS enhancement layer coding algorithm based on interested region is proposed. This algorithm adds the extraction of interested region to FGS enhancement layer coding. According to the extraction results make bit-plane coding. Considering the high residual factor and interested region to arrange the bit-plane. The algorithm not only guarantees the objective video quality, bur also improves the visual quality of the video.Secondly, in order to ensure the coded stream transmission quality in different bandwidth, a multi-path transmission algorithm based FGS is proposed. First, directed diffusion routing protocol is improved to be that between source node and sink node establish multiple paths with different service quality. Then, according to the network bandwidth, different stream layers which have been encoded by FGS be selected for transmission. This algorithm can adapt to different bandwidth. It can not only provide reliable transmission for the basic layer, but also can ensure the video transmission quality. |
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