一种鲁棒的自适应DCT域数字水印算法

A New Robust Image Watermarking Algorithm in DCT-Domain

离散余弦变换(Discrete Cosine Transform,DCT)是数字信号处理技术中最常用的频域变换之一,本文的数字水印算法就是基于离散余弦变换域的算法。本算法以有意义图像作为水印信息,置乱后自适应嵌入到DCT变换后的载体图像,通过计算每块图像的方差确定嵌入信息的块;根据水印信息量的大小决定嵌入块的数量;由密钥产生嵌入的位置。实验证明本算法具有很好的鲁棒性,安全性和不可见性,不失为一优良的数字水印算法。

The Discrete Cosine Transform （DCT） is one of most commonly used digital signal processing technology. In this paper, A robust digital watermarking algorithm is presented in DCT domain, and the image with special meaning is used as watermarking, which is set chaotically to obtain last digital watermarking signal embeded into host image DCT daomian.What is more, the variance of every block is calculated to determine which block is used to embed watermarking signal. Else, the number of block is determined by the number of watermarking signal; Last, the positions, in which the watermarking is embedded, are marked by random sequence produced through the key. Many experiments are the best proof for robustness, the security and invisibility, so we can say that this algorithm is a fine digital watermark one.