Contourlet域的灰度水印技术研究

Researches of Gray Digital Watermarking Technique Based on Contourlet Transform

为了提高水印算法的鲁棒性和安全性,提出一种基于Contourlet域的双重置乱灰度图像水印算法。首先对灰度水印图像进行Amold变换和Baker映射双重置乱处理,提高水印安全性;然后将宿主图像进行Contourlet分解为一系列多尺度、局部化、方向性的子带图像,最后选择Contourlet低频系数嵌入水印,并采用明提取的方法获取水印。实验结果表明,该算法能有效的抵抗JPEG压缩、噪声、剪裁等攻击,具有较好的不可见性和更强的稳健性。

A novel algorithm of double scrambling gray image watermarking is proposed based on Contourlet Transform. A perceived strong and informative gray image is applied to the watermark image to guarantee its robustness and security. After Contourlet transform, host image was decomposed into a series of multi scale,local, and directional subimages. Then, Contourlet transform low frequency subband is embedded into the watermark. And extraction method is used to get the embedded watermark. The experimental results show that the algorithm can effec- tively resist JPEG compression, noise, cropping and other attacks, having good invisibility and better stability.