基于Contourlet变换和奇异值分解的图像零水印算法

提出一种基于Contourlet变换和奇异值分解的数字图像零水印算法。原始图像经过Contourlet变换后，分解为一系列多尺度、局部化、方向性的子带图像，选择对低频子带进行分块奇异值分解，然后根据每块中第一个奇异值的大小特性“嵌入”和“提取”水印。实验结果表明，该图像水印算法能够较好地抵抗JPEG有损压缩、叠加噪声、剪裁等攻击，具有较强的鲁棒性和不可见性，提高了水印识别的可靠性。

Image zero-watermarking algorithm based on Contourlet transform and singular value decomposition

An image zero-watermarking algorithm was proposed based on contourlet transform and singular value decompositon. After the coutourlet transform, the original image was decomposed into series of multi scale, local and directional subimages. The singular value of low frequency component is decomposed. The watermark is embedded and extracted from the first singular value of the every block of image. Experimental results show that the digital image watermarking Algorithm has a good transparence of embedded watermark image and is robust against attacks such as added noise, JPEG compression and cropping. The reliability of watermark extraction was enhanced.