一种基于小波域的彩色图像自适应水印

数字水印作为数字媒体版权保护的有效办法,近年来越来越为人们所重视。该文提出了一种新的基于小波变换的静止的彩色图像数字水印的嵌入和检测算法：算法采用二值图像作为水印,首先利用二维离散小波变换对原始载体图像的蓝色分量进行多级分解,然后置乱二值水印图像,将置乱后的二值水印数据自适应地叠加到图像的第L级水平、垂直和对角线小波系数上实现水印的嵌入,最后进行逆向小波变换生成嵌入水印后的图像。实验结果表明,该算法对JPEG有损压缩、滤波和噪声等水印攻击显示出较强的鲁棒性,取得了隐蔽性和鲁棒性的良好折中,且提取水印时采用了“多数原则”,不需要原始载体图像,水印检测的可靠性得到了很大的提高。

A Color Image-adptive Watermark Based on Wavelet Transform

As an effective way for protecting copyright of digital media,watermark is receiving more and more attention.In this paper,a new method of digital watermark for still color image based on the wavelet transform is proposed.In this method,the watermark is a bilevel image.First,the raw image in multiresolution is decomposed using DWT,then the watermark image is permutated and added into the horizontal,vertical and diagonal wavelet coefficients of multiresolution representation of blue component of the original image in the L layer.Finally the image with watermark is reconstructed using IDWT.Experimental results show that the proposed method is robust against JPEG compression,image processing and attack such as filtering and noise,and receives a good tradeoff between con-cealment and robustness,and the detecting procedure does not need origin host image by "majority principles" and improves the dependability of detecting the watermark.