The Shape Coding Technology Of Object-based Video Coding

Along with the unceasing maturity of multimedia technique, people have advanced new and higher requirements for the processing mode of multimedia and paid more attention to the interactivity and flexibility, such as interactive video programs, the cutting and arrangement of video information, the searches of the video information etc. The methods of the conventional video coding technique were frame-based coding methods, so it is impossible to operate on video content directly. In order to satisfy people's requirements, it needs to exploit new video coding/decoding technique-the object-based video coding/decoding technique. MPEG-4 is the first object-based coding/decoding standard which satisfies the requests.The conventional video coding/decoding technique adopts frame-based coding technique, while MPEG-4 coding/decoding standard adopts object-based coding technique. MPEG-4 standard divides video into different consecutively moving video objects and codes every object separately. Each object includes three kinds of information: the shape information,the texture information and movement information. The three kinds of information of every video object are needed to code. One of the core techniques in MPEG-4 is the part of shape coding. By reason of having adopted the shape coding technique, MPEG-4 has the larruping ability-the content-based interactivity.The shape coding part of MPEG-4 is mainly researched systemically in the dissertation. On the basis of the deep research of CAE (Context-based Arithmetic Encoding) shape coding method, two kinds of new shape coding methods-IPPSC (Improved Pyramid-based Shape Coding) method and UN-PSC(UnionNode-PSC) method are proposed, which are united with wavelet technique and are based on PSC(Pyramid-based Shape Coding) method. The two methods largely improve the performance of PSC method. Experiment results show that these improved methods have many advantages. At one time a new kind of shape coding method-Skeleton-based Decomposition Shape Coding is researched in the dissertation, which is new in this field. The dissertation concludes the characteristics of this method.