基于字符规范化的文档图像水印算法  

Document image watermarking based on character normalization

作　　者：李德鑫[1] 朱宁波[1] 刘伟[1] 

机构地区：[1]湖南大学计算机与通信学院,湖南长沙410082

出　　处：《计算机工程与设计》2007年第19期4690-4691,4701,共3页Computer Engineering and Design

摘　　要：运用字符规范化和小波变换的知识,提出一种将文档图像分割成字符图像,再对字符图像规范化,然后将随机序列嵌入到小波图像低频系数的水印算法。根据视觉系统纹理掩蔽特性,将不同强度的水印分量嵌入到了不同的小波系数中。由于文档图像分割和规范化本身具有抗几何攻击的特性,故该方法对缩放、小角度旋转有一定的鲁棒性,实验结果表明:该方法在文档图像上比其它方法更具备优越性。Knowledge on character normalization and wavelet transform is proposed that divide a document image into character image and normalize these character images, and embeds a random sequence watermarks into a lower frequency subband based on the wavelet coefficient distribution. By exploiting and depending on the feature of visual masking of human vision system, watermark components with different strength are embedded into different wavelet coefficients. Because division of document image and normalization of character image have a feacture against＇geometric distortion, this watermarking algorithm is more robust to ageometric distortions. The experiment prove that this algorithm is superior to other algorithm in document images.

关 键 词：几何攻击 文档图像 小波变换 图像水印 规范化 

分 类 号：TP391.41[自动化与计算机技术—计算机应用技术]