一种基于内容的图像比率可分级编码方法的研究

多分辨率环境下 的多媒体应用导致了基于内容的视频和图像编码的需求。提出一种基于内容的图像比率可分级性编码方法，方法具有以下特点：以不同的任意形状的ROI（Regions of Interest)分别进行独立的 小波分散和编码；采用逐次逼近的量化模式，以形成潜入式码流；解码时，用户可选择相应的ROI进行比率可分级解码。它在一定程度上满足了JPEG－2000中的ROI编码和MPEG－4中的静态图像纹理编码的需求。试验结果验证了方法的有效性。

Research on Content-Based Rate Scalable Image Coding

New applications in a multiresolution environment, such as progressive transmission of image, image database browsing, etc., bring about the need for content-based coding of image and video. In this paper, a new content-based rate scalable image coding algorithm is proposed. First, every ROI (Region of Interest) in the image is extracted and the minimal rectangle region including every ROI is decomposed with wavelet transformation using symmetric extension and padding zero value technology. Second, the wavelet coefficients of every ROI are coded with EZW algorithm so as to produce an embedded bit stream. The proposed algorithm can be characterized by the following properties: 1) Every ROI is coded by itself so as to produce bit stream separatedly. 2) the successive-approximation quantization is used in order to perform the embedded coding. 3) The ROI can be chosen and coded in rate scalable way. This algorithm can be a tool of the ROI coding in JPEG-2000 and the visual static texture coding in MPEG-4. Simulation results show it is effective.