基于DCT变换的彩色图像置乱数字水印算法

介绍了离散余弦变换的系数特征，提出了一种基于离散余弦变换的彩色图像置乱数字水印算法。算法是将数字水印置乱加密后微小的扰动原始彩色图像经离散余弦变换后的对应系数，从而达到数字水印嵌入的目的。仿真实验表明算法简单高效，原图像与嵌入水印后图像差异小，水印提取准确，能较好的保证数字水印不可感知性，在对嵌入水印图像进行各种加噪、裁剪、旋转、锐化等处理后，水印仍有较强的鲁棒性。

A Novel Color Image-Scrambling Digital Watermarking Algorithm based on Discrete Cosine Transform

In this paper, the coefficient features of Discrete Cosine Transform（ DCT） are described and a color image-scrambling digital watermarking algorithm based on DCT is proposed. The scrambled digital watermarking is embedded into original image by subtle perturbations of DCT＆#39;s corresponding coefficients. Simulation experiment shows that the proposed watermarking scheme is feasible and simple, the embedded watermarking images have little difference from the original images,and the extracted watermark is precise and accurate. Moreover,the digital watermark is imperceptible and robust against various signals processing such as noise adding, cropping, rotating and sharpening,etc.