基于小波变换灰度水印的版权保护

Grayscale Watermark for Copyright Protection Based on Wavelet Transform

对于电子出版物和媒介的版权保护,数字水印是当前的研究热点。随着信息技术的快速发展,越来越多的信息需要隐藏在电子媒介当中。提出了基于H arr离散小波变换的灰度水印的一种新算法。对于信息隐藏,提出了像素扩展并且利用H arr离散小波变换进行降维处理的方法。即提出了一个可视的加密方法产生水印的两个随机等份:一个嵌入到封面图像中,另一个作为密钥进行水印提取。利用H arr离散小波变换进行程序处理,并且提取两个等分的主要特征。该方法是为水印专门设计的,且不容易被改变和去除。经过压缩和剪切攻击之后,仍能提取出可识别的图像。

A new algorithm is proposed based on Harr discrete wavelet transform（HDWT） for the grayscale watermark on paper.Digital watermark is a very popular research focus for copyright protection of electronic documents and media.With quick development of information technology,more and more information has been hidden in electronic media.A method is proposed about pixel expansion for information hiding and then applying HDWT to dimension reduction.And a visual cryptographic approach is proposed to generate two random shares of the watermark： one is embedded into the cover——image,the other is kept as a secret key for the watermark extraction later.This procedure would be dealt with by Harr discrete wavelet transform and the primary features of the two shares would be left.This approach is specially designed for watermark and is difficult to change or remove.Even after several compression or cutting attacks,it can still extract recognizable graphic.