基于离散小波变换和奇异值分解的数字水印算法

当前数字作品的版权保护问题备受关注,数字水印是保护数字作品版权的有效手段。本研究针对大容量水印嵌入问题,提出一种基于离散小波变换和奇异值分解的灰度图像数字水印算法。首先,利用离散小波变换将原始图像分为LL、LH、HL和HH四个子带;其次,通过奇异值分解获得LL子带图像的对角矩阵S^l以及水印图像的对角矩阵S^w;然后,将矩阵S^l与S^u进行叠加来完成水印嵌入。该算法的突出特点为嵌入的水印容量大,且算法具有较强的鲁棒性。实验证明,嵌入水印后的图像在经受高斯噪声、椒盐噪声、旋转等攻击后,利用该算法仍能提取到有效的水印图像。

Digital Watermarking Algorithm Based on Discrete Wavelet Transform and Singular Value Decomposition

Nowadays, copyright protection of digital works has gained more and more attention. Digital watermarking is an effective way to protect copyright of digital works. In this paper, the problem of embedding the larger capacity watermarking into an image was studied, and a robust algorithm based on Discrete Wavelet Transform （DWT） and Singular Value Decom- position （SVD） for watermarking grayscale images was proposed. Firstly, a host image was decomposed by DWT into four sub -bands, namely, LL, LH, HL and HH. Next, the diagonal matrix Sl of the low -frequency LL image and the diagonal matrix Sw of the watermarking image were gained by SVD respectively. Then, Sl and SWwere superposed together to accom- plish watermarking embedding. The outstanding features of the proposed algorithm are that it provides larger watermarking capacity and is more robust than others. Experiments showed that the proposed approach is robust against most of usual at- tacks, such as Gaussian Noise, Salt ＆ Pepper, rotation, etc.