基于PCA和混沌置乱的零水印算法  

Zero-watermark algorithm based on PCA and chaotic scrambling

作　　者：胡裕峰[1] 朱善安[1] 

机构地区：[1]浙江大学电气工程学院,浙江杭州310027

出　　处：《浙江大学学报（工学版）》2008年第4期593-597,共5页Journal of Zhejiang University：Engineering Science

摘　　要：针对传统的数字水印技术在图像中嵌入水印信息会导致图像在一定程度上的失真,且图像受到各种攻击后难以提取出水印的问题,提出了一种零水印算法,该算法可在不导致图像任何失真的情况下起到版权保护的作用.对图像进行分块和主成分分析(PCA),得到图像的主要分量,基于Renyi映射生成混沌序列对图像的主要分量进行位置置乱,比较置乱后相邻主分量系数间的大小生成特征水印.当对待认证图像进行认证时,用同样的方法提取该认证图像的特征水印,比较两特征水印的相似度来判断图像的版权和所有权.实验结果表明,该算法的不可察觉性很好,并对一些常见的攻击,如JPEG压缩、剪裁、加噪、滤波和旋转等有很强的鲁棒性.与小波域内图像零水印算法的比较结果证明了该方法具有更强的鲁棒性.Traditional digital watermarking techniques that protect the image copyright by embedding the watermark into image would lead to distortion, and it is difficult to extract watermark from attacked images. To solve the problem, an image non-watermarking method was proposed, which could protect the image copyright without affecting the image quality. The image was subdivided block by block and principle components analysis （PCA） was used to decorrelate the image pixel to obtain the principle components of an image. The chaotic sequence was generated based on Renyi mapping and the principle components were thrown into confusion. Then the coefficients of the confused principle components were compared to generate the characteristic watermark. The same process was done to draw out the characteristic watermark from the authentication image, and the conformability of two watermarks was analyzed for judging the copyright and ownership of the image. Experimental results show that this method is invisible and robust against some usual attacks such as JPEG compression, cropping, adding noise, filtering and rotation and so on. Compared with the image non-watermarking method in discrete wavelet transform domain, this algorithm was proved to be more robust.

关 键 词：主成分分析 Renyi映射 随机置乱 零水印 

分 类 号：TP391[自动化与计算机技术—计算机应用技术]