基于QR码的抗几何攻击数字全息水印

Holographic Digital Watermarking Algorithm Against Geometric Attacks Based on QR Code

目的针对含水印QR码图像在扫描和解码过程中的几何攻击,提出一种基于数字全息和傅里叶-梅林变换的数字水印技术。方法以傅里叶-梅林变换构建几何不变域,并利用全息图的不可撕毁性,将水印以全息图的方式隐藏在QR码图像离散傅里叶变换中频幅度谱部分。结果通过对比实验表明,提出算法可以有效抵抗对含水印QR码图像进行的剪切、缩放和旋转等几何攻击,且算法简便,嵌入信息量大。结论在不影响QR码正确识别的基础上,提出算法的鲁棒性和不可见性之间能达到较好的平衡。

Targeting at the geometric attack problem of QR code watermarked images in the process of scanning and decoding, a new watermarking algorithm was proposed based on digital holography and Fourier-Mellin transform. Fourier-Mellin transform was used to construct geometric invariant domain, and holographic watermarking was embedded in the middle frequency of the QR code image＇ s DFT amplitude spectrum domain taking advantage of the strong anti-tear property of hologram. Comparative experiments showed that the algorithm proposed could effectively resist geometric distortion （rotation, scaling, clipping, and so on） of QR code watermarked images, and this algorithm was simple and had large amount of embedded information. The algorithm proposed in this paper could well balance between the robustness and the invisibility without affecting the correct identification of QR code.