| With uninterrupted increasing of communication services in morden society, the contradiction between multimedia correspondence and telecommunication networks capability has become more aculeated, which restricted the development of digital communication greatly. The development target of multimedia technolodge is to resolve this contradiction.Firstly, the paper describes the progress and actuality of multimedia coding and decoding and digital video surveillance and control system. Then, it introduces a series of multimedia standards.In which MPEG-4 coding process mainly divided into the following parts: shape coding, athletic coding and venation coding, and emphasly analyses the block matching, diamond searching, DCT, quantify and variable length coding.The main innovating point of MPEG-4 is content-based coding. It needs to break down the object to video object plane which contains semantic meaning. But the VOP segmentation doesn't get the attention as the athletic segmentation.The VOP segmentation is divided into two types: one is the background and VOP moved simultaneity (vidicon moving); the other is the background still, but the VOP athletic (Surveillance and Control System of certain department). Because of this paper aimed at the second type, this paper brings forward the VOP segmentation through estimating background. The paper has carried on the test on the improved and the improvement algorithm in the actual video frequency sequence, contrasts and analyzes the testing result. Result shows that the improvement algorithm has move superior function than the improved.When used the improvement algorithm in actual video surveillance and control system we find that the complete still background is not exists. To solve this problem, the paper uses one way which the background is updated slowly when the scene changed. This method is tested actually. Result shows that it can segment VOP better. At last we test the improvement coding and encoding system in actually. Result shows that compression ratio is been enhanced in keeping the quality of image. |
