Variable-Code-Mode-Based Connectivity Compression for Triangular Meshes

DOI：

 作者 单位 刘 迎 中国科学院 软件研究所 计算机科学国家重点实验室,北京 100080 中国科学院 研究生院,北京 100049 刘学慧 中国科学院 软件研究所 计算机科学国家重点实验室,北京 100080 中国科学院 研究生院,北京 100049 吴恩华 中国科学院 软件研究所 计算机科学国家重点实验室,北京 100080 中国科学院 研究生院,北京 100049 澳门大学 科学技术学院 电脑与资讯科学系,澳门

针对三角网格模型的拓扑信息,提出了一种高效压缩方法.不同于以往的单纯利用算术编码或霍夫曼编码对遍历三角网格生成的拓扑流进行编码压缩,根据三角网格模型(特别是规则三角网格模型)的特点,自适应地提高编码过程中对当前编码字符发生的预测准确率,实现对三角网格模型的拓扑信息的高效压缩.算法首先遍历三角网格模型,得到操作符序列;然后对得到的操作符序列的每个操作符作模版可变的自适应算术编码.在编码过程中,根据当前编码字符的前一个操作符、三角网格模型的特点以及网格遍历方法为当前编码操作符计算一个模版,在这个模版中,预测准确率高的操作符用较短的二进制串表示.根据当前编码操作符的可变模版,可以得到该操作符的二进制表示,并对这个二进制表示的每个比特作自适应算术编码.该方法是针对流形三角网格模型的拓扑信息作单分辨率的基于面的无损压缩,可以得到很好的三角网格拓扑信息的压缩结果,其压缩比甚至比拓扑压缩领域压缩比方面最好的TG算法的压缩比还要好.

This paper presents an efficient algorithm for encoding the connectivity information of triangular meshes. In the previous algorithms, Huffman or arithmetic coding method is directly used to encode operator series, but in comparison in this method, it can efficiently improve the compression ratio of connectivity information by predicting correctly the operator currently being encoded. By the method, all triangles are traversed first to obtain operator series. Then an arithmetic coder based on variable code-mode is applied to encode the operator series. According to the operator last encoded, the property of triangular mesh and the method of mesh traversal, a code-mode is calculated for each operator currently being encoded, where the operator with higher prediction probability is given a shorter binary strand. Then the binary strand can be obtained according to its code-mode and encode every bit of this binary strand by adaptive arithmetic coding method. The algorithm is a face-based method and also a single-resolution lossless compression method for manifold triangular mesh. Testing results show that the compression ratio of the algorithm is very high and even higher than the compression ratio by using TG algorithm, which is commonly regarded as one of the best in terms of compression ratio.
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