基于QR码的Contourlet域数字水印算法

Digital watermarking scheme in Contourlet domain based on QR code

针对目前数字水印技术无法有效抵抗几何攻击的问题,本文提出了一种基于QR码的Contourlet域数字水印算法。将文字信息进行QR码编码作为水印信息。首先,将载体图像进行Contourlet变换;然后,将得到的低频逼近图像进行分块;最后,将每一位QR码水印信息以量化的方式对应嵌入到每一个子块中。实验结果表明,本算法可以抵抗任意角度旋转和任意等比例缩放攻击,同时对高斯噪声、Speckle噪声、均值滤波、高斯滤波和JPEG压缩攻击具有很强的鲁棒性,并且算法复杂度低;水印提取时不需要借助原始图像,属于盲水印。因此,本文提出的数字水印技术可以广泛应用在数字产品的版权保护中。

Image watermarking against geometric attacks remains to be the hotspot and challenging point in the present research on watermarking. The existing watermarking algorithms can not resist geometric attacks efficiently. For addressing the problem,a Contourlet-domain watermarking algorithm resistant to geometrical attacks based on QR code is proposed. The watermark in this paper is QR code encoded from text message. Firstly,the original image is decomposed by Contourlet transform. Then, the low-frequency sub band of the Contourlet coefficients is divided into sub-blocks. Finally,each bit of QR code is embedded into each sub-block repeatedly. Experimental results demonstrate that this method can well resist at tacks such as rotation, scaling, Gaussian noise, speckle noise, average filtering, Gaussian filtering and JPEG lossy compression,and its algorithm complexity is lower. In the phase of watermark extraction,the original image is not needed. The proposed algorithm is blind. The watermarking technology proposed can be widely used in copyright protection of digital products.