基于DCT域改进的自适应数字水印算法

针对DCT变换特点,提出一种改进的自适应水印算法.选取3个DCT中频系数,求均值及DCT矩阵主对角线均值,比较嵌入位与它们的关系,调整嵌入位的大小实现水印自适应嵌入.水印信息经过Arnold置乱后嵌入到原始图像.实验表明,该算法隐蔽性良好,水印提取效果较好,对旋转、剪切、滤波、JPEG、修改等攻击具有较好的鲁棒性和稳健性.

Improved adaptive digital watermarking algorithm based on DCT domain

An improved self- adaptive digital watermarking algorithm has been proposed based on the characteristics of Discrete Cosine Transformation( DCT). It selects three medium- frequency DCT coefficients and coefficients of the main diagonal with DCT matrix,calculates their means,and then compares the embedded coefficient with these two means to achieve watermarking embedded adaptively by adjusting the value of embedded coefficient. The watermarking has been processed by Arnold transformation and embedded in the original image. The experiment shows that this algorithm has a better invisible effect of extracting watermarking,enough robustness and toughness for some image processing operations,such as rotation,cutting,filter,JPEG compression,altering,etc.