基于小波变换的图像水印算法

数字水印为数字媒体版权保护的有效方法，提出了一种在小波变换域中加入水印的算法，该算法利用小波变换的特性，选择在较低频于带的重要系数中加入水印。首先选择需要添加水印的子带，并确定一组门限，构成一组区间，通过改变幅值落在这些区间的小波系数来加载水印信息，水印为一伪随机序列，检测时通过计算原始随机序列与恢复出的随机序鲁的互相关来判断水印是否存在。实验结果表明，应用所提出的算法实现的水印对于常见图像处理有

Image Watermarking Algorithm Based on Wavelet Transform

Digital watermarking represents a valid solution to the copyright protection. A watermarking algorithm based on wavelet transform was proposed. This algorithm takes advantages of the wavelet transform and adds watermark onto the important wavelet coefficients located in the low frequency sub band. A group of thresholds are selected and the watermark are embedded by modifying the coefficients whose amplitude is between these thresholds. The watermark is a pseudo random sequence and its existence can be judged by calculating the correlation of the original sequence and the detected sequence. The experimental results demonstrate that the watermark generated with the proposed algorithm are invisible and robust against commonly used image processing techniques.