一种鲁棒的文档图像数字水印算法

基于文档图像的特征,本文提出了一种在文档图像空间域,使用余弦波作为水印序列,通过改变文档中的每个字符的灰度值来达到嵌入水印目的水印算法。利用Arnold变换对水印序列进行置乱,消除象素的空间相关性,增加水印的安全性。通过实验结果和理论分析可知本算法对各种压缩,剪切,噪音攻击具有很高的鲁棒性。对于字符较少的文档图像,此算法效果不理想,尤其对空白文档图像,不能适用此算法。

Because of document images own characteristics,watermarking algorithm proposed in this paper in the document image space domain,by changing the character of each document in the gray value to achieve the purpose of embedding the watermark,the watermark embedded image of this article is a cosine wave.Using Arnold transform the watermark sequence scrambling to eliminate pixel spatial correlation,increasing the security of the watermark.Through experimental results and theoretical analysis of the algorithm,we can see a variety of compression,shear cutting,the noise has a high attack robustness.The capacity of watermark embedding is not a great need for scaling attacks the relevance of the new watermarking algorithm for document image with fewer characters,the algorithm result is not satisfactory,especially for a blank document images,this algorithm can not be applied.