一种基于分块DCT变换的三维网格模型半脆弱水印算法

摘要

半脆弱水印可区分恶意攻击和正常数据处理，具有更广泛的适用性，但目前已提出的算法大多只能容忍少数类型的网格正常处理。文中提出了一种基于内容认证的半脆弱水印算法，网格分割后水印隐藏在各分块的DCT变换域系数中，网格被非法篡改时，通过匹配提取出的水印序列与原始水印序列可定位出篡改位置。实验结果表明，算法嵌入的半脆弱水印可容忍多种类型的网格正常数据处理，如网格RST相似变换和低强度的顶点坐标值量化处理，同时对恶意攻击表现敏感，可较准确的定位出篡改位置，并能以直观的可视化形式做出标记。%Semi-fragile watermark has wider applicability,as it can distinguish malicious tampering and normal mesh processing.Most present algorithms can only tolerate a few types of normal mesh processing. A novel semi-fragile watermarking algorithm based on mesh content is proposed.In this algorithm,mesh is partitioned into some sub-meshes,and semi-fragile watermarks are hidden in DCT coefficients of each sub-mesh.When mesh is tampered,the position occurred can be located by matching the extracted wa-termark sequence and original watermark sequence.Experimental results show that the proposed algo-rithm can tolerate various mesh normal processing,such as mesh RST similar transforming,and quantiza-tion of vertex coordinates with low intensity,while is sensitive to malicious tampering.The proposed algo-rithm can also locate the tamering positions with relatively high precision.