一种基于小波变换的图像盲水印算法

数字水印技术作为数字产品版权保护的一项新技术,已受到越来越多的关注,基于小波变换的数字水印技术也成为当前的一个研究热点。为保证水印的隐蔽性和鲁棒性,提出了一种基于小波变换的图像盲水印算法,即在嵌入之前先对水印做置乱处理,然后将水印信息与扩频序列进行扩频调制后,结合人眼视觉系统的纹理掩蔽特性和刚刚可分辨门限嵌入到载体图像的小波变换域。最后利用扩频序列的自相关函数特征检测出水印信息,检测过程中不需要原始载体图像。实验结果表明,该算法嵌入水印后不易被察觉,检测出的水印效果好,对JPEG有损压缩、裁剪、噪声干扰和低通滤波有较强的鲁棒性。

A Blind Image Watermark Algorithm Based on Wavelet Transform

As a new technique applied to protecting the copyright of digital productions, the digital watermark technique has drawn extensive attentions. The watermark technique based on wavelet transform has been an active study field. In order to ensure the concealment and robustness of watermark, a blind image algorithm on the basis of wavelet transform was proposed. Firstly, watermark was scrambled before the algorithm was embedded. Then watermark information and spread spectrum sequence are modulated, and combining texture concealable characteristics of human vision system with just differenthating limit, were embedded into DWT domain of carrier image. Finally, making use of autocorrelation function characteristic of spread spectrum sequence, watermark information was detected. In the detection process, it is not requisite for initial carrier image. The experiment results demonstrate that with the algorithm embedded watermark, watermark is not easy to be found out. It has a fine detected watermark effect. The algorithm is robust enough for JPEG degradation compression, clipping, noise attacks and low-pass filtering.