为提高不可见水印的鲁棒性,提出一种基于奇异值分解的小波域数字水印方法.该方法首先将原始载体图像进行2级小波变换,对第2级对角细节子图进行奇异值分解,得到水印嵌入位置;然后对二值图像水印进行Arnold变换和一维化处理,获得待嵌入的水印比特流,并根据该比特流和奇异值矩阵中各元素的不同组合嵌入水印;最后经小波子图重构和小波逆变换得到含水印的载体图像.实验结果表明:在噪声干扰、滤波、压缩、旋转、缩放、剪切等多种攻击下,该方法明显优于现有的一些奇异值水印方法.
To improve the robustness of invisible watermarking, this paper proposes a watermark- ing method based on singular value decomposition (SVD) and discrete wavelet transform. In this method, techniqu after the original cover image is decomposed by a 2-Level wavelet transform, the SVD e is employed to the matrix composed by the second detail coefficients to acquire the em- bedded positions. On the other hand, the original binary image watermark is scrambled with Ar- nold transform and then is changed into a one-dimensional bit stream. According to the different combinations of the bit stream and the elements in the singular value matrix, the bit stream of watermark is embedded into the cover image. Experimental results show that the proposed meth- od is superior to some other SVD-based methods when the cover image is suffered from any an at- tack, such as noise-disturbing, filtering, compressing, rotating, rescaling, cropping etc.