一种鲁棒的3维网络模型数字水印算法

A Robust 3D Mesh Watermarking Scheme

提出一种新的空域盲检测3维网格模型数字水印算法,它主要利用主成分分析(PCA)和顶点分组技术。首先,使用PCA计算3维模型顶点坐标协方差矩阵的3个特征向量,把笛卡儿坐标系的3个坐标轴与这3个特征向量对齐。接着以伪随机数产生的向量为中心向量,构造一些互不重叠的圆锥状空间(bin空间)。最后,先将3维网格模型的所有顶点分组到对应得bin空间里,再把每个bin空间量化成若干个子空间用来嵌入水印。实验结果表明,该算法对仿射变换、顶点乱序、噪声等攻击有较强的鲁棒性。

This paper proposed a novel robust oblivious watermarking scheme in the spatial domain suitable for 3D mesh object, which combines the principal component analysis （PCA） method with construction of cone bins. Firstly, PCA is used to calculate the eigenvectors of covarianee matrix of vertex coordinates. Then the object is rotated and translated so that its center of mass and the three eigenvectors that coincide with the origin and the three axes of the Cartesian coordinate system. Subsequently, many cone bins are constructed, each bin center according to two angle parameters of spherical coordinate produced by pseudorandom number generators and the vertices are classified into the appropriate cone bins. Each cone bin is divided into a number of sub-bins in order to embed the watermark bit, and the size of sub-bin can make tradeoff between invisible and robustness. Experiment results show the remarkable ability of the proposed mechanism to resist against various attacks such as adding noise, clipping, similarity transform and vertex re-ordering.