基于数字全息及失真校正的抗打印扫描数字图像水印

摘要

提出一种基于数字全息及失真校正的抗打印扫描数字图像水印方法,将水印以数字全息图的方式隐藏在载体图像离散傅里叶变换(discrete Fourier transform,DFT)幅度谱中,由载体图像纹理控制的峰值信噪比设定阈值,自适应调节水印嵌入强度.该方法利用了数字全息图的特点,采用基于DFT和边缘检测算法校正打印扫描图像的旋转失真,因而可从打印扫描图像中准确提取水印信号.相比以往同类水印算法,所提方法具有优良的不可见性和鲁棒性,以及较大的水印嵌入量.%This paper presents a novel print-scan resilient watermarking algorithm based on digital hologram and correction of distortion. A hologram of the watermark is obtained and embedded into the spectral magnitude of the host image. A PSNR threshold adapted to the texture of the host image is set to adjust the watermark strength. The rotation distortion due to the print-scan process is corrected based on discrete Fourier transform (DFT) and edge detection. The method makes use of the digital hologram characteristics, and is capable of extracting the embedded watermark from a print-scan version reliably. Compared with previous similar schemes, the proposed approach shows advantages in invisibility, robustness and embedding capacity.