基于三维动画镜头数据和Cholesky分解的水印算法

WATERMARKING ALGORITHM BASED ON 3D ANIMATION LENS DATA AND CHOLESKY DECOMPOSITION

三维动画因生动逼真、高信息量的优点,被广泛应用于影视广告及虚拟展示等领域.但随之引发的下载、拷贝,甚至修改作者、篡改信息等恶意行为越来越严重,给中国动漫行业在国际上的声望造成了极坏的影响.提出一种数字水印算法,将数字水印这种信息安全方法应用到三维动画领域,以保护三维动画的版权,水印的嵌入载体选择的是动画中的镜头数据.收集一部三维动画中的镜头数据,形成一个矩阵,对此矩阵进行Cholesky分解,得到一个下三角矩阵;把水印信息矩阵LU分解后的元素嵌入到下三角矩阵中,完成水印的嵌入;用更新后的下三角矩阵重构镜头数据矩阵;用新的镜头数据重新约束动画中的镜头,从而得到嵌入了水印的三维动画.通过对三维动画进行修改镜头、修改环境效果等攻击,验证得出算法具有较高的水印嵌入量、良好的隐藏性和抗攻击性,可以推广使用.

3D animation is widely used in the fields of film and television advertising and virtual display due to its vivid and high information content.However,the subsequent malicious ACTS like downloading,copying,even modifying authors and tampering information have become more and more serious,which has caused extremely bad influence on the international reputation of China s animation industry.This paper proposes a digital watermarking algorithm,which applies it as an information security method to the field of 3D animation to protect the copyright.The embedding carrier of watermarking was lens data in animation.We collected the lens data in a 3D animation and form a matrix,and Cholesky decomposition was used to get a lower triangle matrix.Then the LU decomposed elements of the watermarking information matrix were embedded into the lower triangular matrix to complete the watermarking embedding.The lens data matrix was reconstructed with the updated lower triangular matrix.Finally,the new lens data was used to re-constrain the lens in the animation,and the watermarked 3D animation was obtained.Through the attack of modifying lens and environment effects of 3D animation,it is proved that the algorithm has high embedding amount of watermarking,good hiding and anti-attack,and can be widely used.