基于DCT和SVD的图像哈希水印算法

为使频域水印技术更好地应用于数字图像的版权保护,提出一种基于离散余弦变换和奇异值分解相结合的图像哈希水印算法。利用DWT变换提取载体图像的低频系数矩阵构造水印;对载体图像进行分块DCT变换,提取每个子块的低频系数;对低频系数所组成的矩阵进行SVD变换,在对角阵上嵌入水印;对频域系数进行逆变换得到含水印图。将已有算法和当前所提出的算法进行对比,实验结果表明,所提水印算法具有良好的不可感知性和鲁棒性。

Image hash watermarking algorithm based on DCT and SVD

To improve the application of frequency domain watermarking technology in copyright protection of digital images,an image hash watermarking algorithm based on discrete cosine transform and singular value decomposition was proposed.DWT transform was used to extract the low-frequency coefficient matrix of the carrier image to construct the watermark.The carrier image was subjected to block DCT transformation to extract each low-frequency coefficient.SVD transformation was performed on the matrix composed of low-frequency coefficients,the watermark was embedded on the diagonal array.The frequency domain coefficients were inversely transformed to obtain the watermarked image.The existing algorithm was compared with the proposed algorithm.Experimental results show that the watermarking algorithm has good imperceptibility and robustness.