一种新的DWT与DCT相结合的图像盲水印算法

A New Image Watermarking Algorithm Based on DWT and DCT

图像中嵌入的多为二值水印,抗攻击能力有待提高,为了增强算法的鲁棒性,提出基于DWT与DCT结合的新的二值水印图像嵌入算法。该算法首先对二值水印进行Arnold置乱预处理,再对置乱后的水印信息进行混沌加密,对所选取的载体图像进行两级小波变换,选择第二层的细节子带HH2嵌入加密后的二值水印。嵌入水印时对所选取的细节子带HH2进行8×8分块DCT变换,然后采用交换中频系数并引入阈值的方法将加密后的水印嵌入,为增强算法的抗攻击能力,通过仿真实验选择合适的中频系数和阈值。结果表明,该文提出的算法抵抗剪切、高斯及脉冲等噪声、直方图均衡化、调整亮度及对比度、JPEG压缩攻击的效果较好。

For embedding in the cover image are mostly binary watermarks, anti-attack capability needs to be improved. In order to enhance watermarking robustness of the algorithm, this paper proposes a binary watermarking algorithm based on DWT and DCT. Firstly, the binary watermark image is preprocessed by Arnold scrambling, and then the watermark chaotic encryption. Secondly, after decomposing the selected cover image into the secondary layer, HH2 of the secondary layer are selected to em- bed encrypted watermark. HH2 is applied 8 x 8 block DCT and adopt an improved approach to embed encrypted watermark by switching two middle frequency coefficients. In order to enhance the robustness, the embedding suitable intensity factor with the subband. Finally, the simulation experiments show that the method has strong robustness to cutting, image adding noise, histo- gram equalization, JPEG compression.