基于内容认证的三维网格模型半脆弱水印算法

摘要

A novel semi-fragile watermarking algorithm based on content certification is proposed.After processing the calibration on 3D mesh model by principal component analysis,the algorithm constructs spherical coordinates mapping square-matrix with geometric data of model’s vertex to realise 2D parameterisation.The semi-fragile watermark embedded is a binary image,by embedding it into the coefficients of square-matrix,the square-matrix of 3D mesh model with modified coefficients is derived.It is able to judge whether a semi-fragile watermark has gone through illegal tampering by detecting the integrity of it extracted from the suspected model.Experimental results show that the semi-fragile watermark embedded by the algorithm can tolerate a variety of mesh normal data processing,such as mesh translation, rotation,isotropic zooming processing,as well as the low intensity vertex coordinate quantisation processing and vertex random noising,etc., but it is sensitive to malicious tampering such as vertex random noising with high intensity.%提出一种新的基于内容认证的半脆弱水印算法。在对三维网格模型进行主元分析校准处理后，以模型顶点几何数据构造生成球面坐标映射方阵实现二维参数化。嵌入的半脆弱水印为一幅二值图像，将其嵌入到方阵的系数得到三维网格模型的修改系数方阵，可通过检测可疑模型提取出的半脆弱水印的完整性来判断其是否经历过非法篡改。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，例如网格平移、旋转、各向一致缩放处理，以及低强度的顶点坐标量化处理和顶点随机噪声等，对于恶意攻击（例如较高强度的顶点随机噪声）则表现敏感。