基于Contourlet变换的彩色图像双水印算法

Dual watermarking algorithm of colored image based on Contourlet transform

针对一些用于标识和篡改定位的双水印在抗几何攻击方面表现不好的问题,提出了一种基于Contourlet变换的彩色图像双水印算法。该算法首先在红绿蓝(red green blue,RGB)颜色空间,对G分量进行Contourlet变换和QR分解后嵌入鲁棒水印;其次,提取R、G、B三个通道的特征信息,构成可对该图像进行篡改定位的脆弱水印,在B分量上嵌入该脆弱水印,得到含双水印的彩色图像;最后,采用盲提取水印算法提取脆弱水印和鲁棒水印。选取不同刑侦图像进行实验,实验结果表明,脆弱水印能够准确检测篡改位置;鲁棒水印在抵抗剪切、旋转、缩放、随机打马赛克、噪声等几何攻击方面鲁棒性较好。

For the problem that dual watermarking algorithms for identification and tampering are not well in anti-geometric attacks,a color image dual watermarking algorithm based on Contourlet transform is proposed.After Contourlet transform and QR decomposition,the robust watermark is embedded in the G component of the RGB color space.A fragile watermark with the image feature information and used for tampering is formed.A color image with dual watermark is formed,after embedding the fragile watermark in the B component.Fragile watermark and robust watermark are extracted using blind extraction method.For the experiment,different criminal investigation images are chosen.The experimental results show that tamper location can be accurately detected with fragile watermark and the robust watermark is robust in resisting geometric attacks such as shearing,rotation,scaling,random mosaic,and noise.