一种DCT变换域的鲁棒数字水印

提出一种以二值图像为水印的离散余弦变换(DCT)域数字水印算法，对水印图像进行Arnold置乱，用置乱次数作为提取时的密钥，将置乱后的水印图像和载体图像分别进行分块DCT。为了使嵌入的水印具有较强的鲁棒性，把水印的每个子块同时嵌入到多个载体图像的子块中，按照奇数块和偶数块分别将水印嵌入到直流分量和交流分量的中频系数中，实现水印的完全嵌入。实验结果证明，该算法具有良好的鲁棒性和不可见性，能够抵抗有损压缩、剪切、随机涂改和白噪声等攻击。

Robust Digital Watermark on DCT Transform Domain

After taking binary image as watermark,this paper proposes a robust digital watermark arithmetic based on Discrete Cosine Transform（DCT） transformation domain.The watermark image is scrambled,and scramble number is used as the key when extracting watermark,then the watermark image and initial image respectively in block DCT transform are transformed.Each block of the watermark image is embedded into a plurality of the blocks of the initial image in order to make the embedded watermark have strong robustness.Experimental results prove that the arithmetic is of better robustness,invisibility,and resistance the attack to loss compression,cropping,randomly altered,white noise and so on.