基于小波变换的可扩展网格编码
Scalable Mesh Coding Based on Wavelet Transform
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摘要: 为了使位流可以适应网络带宽的异构、时变以及各个网络终端的不同图形处理能力,在网格压缩中引入了位率可扩展性和分辨率可扩展性的概念,提出一种基于小波变换的渐进压缩方法来产生同时具有位率和分辨率可扩展性的位流.该方法将各个子带独立进行编码,对每个子带中的小波系数,按确定的扫描次序转换成一维序列,量化后进行位平面编码.设计了一种自适应细分信息编码算法,使解码端知道每一个小波系数应该放置在哪一个顶点上.实验表明,该方法的位流大小约为PGC方法的70%左右,且具有PGC所不具有的分辨率可扩展性.Abstract: In order to adapt bitstreams to the heterogeneity and variation of network bandwidth and different graphics processing capabilities of network terminals, the concepts of rate scalability and resolution scalability are introduced into mesh compression. A progressive mesh compression method based on wavelet transform is proposed which can generate the bitstreams with both rate and resolution scalability. In the proposed method, each subband is encoded independently. The wavelet coefficients in each subband are scanned into a sequence in a determined order, then are quantized and bitplane encoded. In order for the decoder to know at which vertex each wavelet coefficient should locate, an adaptive subdivision information coding algorithm is designed. The experiment results show that the bitstream size of the proposed method is about 70% of that of PGC method. The proposed method also possesses the resolution scalability PGC does not possess.