郗艳华

摘要：针对二值文档图像的连通性是其拓扑结构的特点，提出对基于图像连通性不变文档水印算法的鲁棒性进行研究。利用可翻转像素标准确定可翻转像素，然后将加密后水印信息代替可翻转像素实现水印嵌入，对含水印图像进行噪声攻击和局部篡改的鲁棒性分析。实验结果表明，该算法具有良好的不可见性，能够抵抗噪声攻击，并且也能抵抗删除、修改和添加等局部篡改攻击，其特点可用于对一些文档图像的版权保护。

关键词：文档水印；连通性；鲁棒性

中图分类号：TP391.9文献标识码：A文章编号：1009-3044(2012)23-5712-03

Robust of Document Watermarking Algorithm Based on Connectivity-Preserving

XI Yan-hua

(School of Physics and Electronics Engineering, Xianyang Normal University, Xianyang 712000, China)

Abstract: For the binary document imagesconnectivity is its topology, the robust of the document watermarking algorithm by connectiv? ity-Preserving is analyzed. The criteria of the flippable pixels are used to judge the flippable pixels. The watermarked image can be ob? tained by inserting the encryptedwatermarking into the flippable pixels. The watermarking is performed by extracting the central pixel in the embeddable blocks. Experiments show that the watermarked document image has good quality. The algorithm has robustness for the noise attackand local tampering attack such as deletion, modification and addition.It can be used to protect the copyright of the binary document images.

Key words: document watermarking; connectivity; robust

1概述

随着计算机网络通信和多媒体技术的发展，有关文该文档的版权保护以及内容认证越来越受到广泛重视。数字水印技术作为保护数字文档图像版权和完整性的有效手段，已成为信息安全领域的研究热点。对于数字文档图像来讲，一种典型算法是通过在空间域翻转图像中对视觉影响较小的个别像素来嵌入水印。

文献[1]根据翻转像素引起的图像块连通性与平滑性的变化情况，通过翻转图像块中优先级别高的像素点进行水印嵌入。文献[2]提出了利用图像块连通性不变确定可翻转像素，然后利用hash函数对除去可翻转像素的图像进行一系列加密处理后前后进行水印嵌入，该方法用于图像完整性认证。由于二值文档图像的连通性是其拓扑结构,当其经受平移、旋转、拉伸、压缩、扭变等操作后,其连通性是不变的。所以该文对文献[2]中提出的基于图像连通性不变的水印算法的鲁棒性进行研究分析。……