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 ,选择在较低频子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列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很好的坚固性 Digital watermarking is an effective method for digital media copyright protection.This paper proposes an algorithm for watermarking in wavelet transform domain, which uses the characteristics of wavelet transform to select watermarking in the important coefficients of lower frequency subbands Watermark sub-band is added, and a set of thresholds is determined to form a set of intervals. The watermark information is loaded by changing the wavelet coefficients whose amplitudes fall in these intervals. The watermark is a pseudo-random sequence. During the detection, by calculating the original random sequence and recovering Of the random sequence of cross-correlation to determine whether the watermark exists.Experimental results show that the proposed algorithm to achieve watermarking for common image processing has good robustness