随着网络多媒体技术的不断发展，版权保护问题变得十分重要。数字水印是实现版权保护的一种非常有效的方法，本文分析了数字水印的特点、分类、应用范围，在充分考虑人眼视觉特性的基础上，对基于人眼视觉的离散小波变换数字水印算法进行深入地研究。 小波变换的基本思想是将图像多分辨率分解到时间域和空间域上，不同的分解尺度对应不同的频率范围。低频分量保留了图像的主要信息，决定了人眼的感知度，而高频分量集中了图像的边缘和纹理特征，如果把水印嵌入到低频，会导致图像的视觉效果下降，如果把水印嵌入到高频，则经过一般图像处理后，高频部分的信息容易丢失，鲁棒性会降低。基于以上因素，应该将水印嵌入到图像的中频系数中，这样保证了水印的不可见性，也加强的算法的鲁棒性。 为了水印图像能更好的抵抗各种攻击，本论文结合人眼视觉特性、正负调制技术及Hopfield网络的联想记忆功能，提出了小波域低、中频域的水印嵌入及提取算法，算法综合运用Arnold置乱变换，进一步增加水印的安全性。试验结果表明改进后的水印算法，能够使水印的不可见性、强壮性及容量三者之间达到很好的平衡，对水印图像的噪声攻击、压缩及剪切攻击都有较强的鲁棒性，是一种切实可行的算法，对现有的小波域数字水印算法具有非常积极的意义。

With the growth of network and multimedia technology, the copyright protection becomes more and more important. In this thesis, analyze the characteristic, classes and application area of the digital watermarking, and then introduce DWT digital watermark algorithm combines with the human visual system and the improved algorithm. The main idea of the use of wavelet transform in image processing is that signal is expressed on time field and scale domain，decomposition dimensions of domain being to should indifferent frequency range. The low frequency tape has kept the main information of the image and it decide the human apperceive degree，but the edge and the texture features of the image are general to concentrate in the high frequency tape, if we add the watermarking to the low frequency tape，it can lead to the reduce of the visual effect of image，if we add the watermark into the high frequency tapes then the information of the high frequency tape will be lost after general image processing，and the robustness of the digital watermarking will be reduced. Considering the above all，we should add the watermark into the intermediate frequency tapes，then the invisibility will be assured and the robustness of the algorithm will be enhanced. In order to make watermark image better resist to various attacks, the watermarking and the embedding algorithms in low and middle domains，associated with the human visual system , modulation of positive and negative and associative memory function of Hopfield network, are proposed.To increase the security of watermarking , convertion of Arnold is used in the algorithm. The result of the experiment indicates that the algorithm improved can balance the invisibility the steadiness and its capability，the algorithm can assure the robustness to familiar image process such as noise contamination，compression and cropping，it is a feasible algorithm and it make an active sense to the present wavelet digital watermarking algorithm.