采用DFT域嵌入的全息水印方法

摘要

研究了基于计算数字全息的数字水印技术,针对水印的稳健性与不可见性的矛盾,提出了一种基于离散傅立叶变换域嵌入二值全息图的数字水印算法,并进行了计算机仿真实验.本算法首先生成二值水印图像的傅立叶全息图并进行二值化,再对载体图像进行傅立叶变换,将二值化的全息图嵌入到载体图像傅立叶变换幅度谱中.使用该方法嵌入的水印具有良好的不可见性和稳健性,通过仿真实验证明,加水印图像的峰值信噪比高且对常见的图像处理都具有良好的稳健性.%This paper studies the watermarking techniques based on Computer Generated Holography. Given that it is always a contradiction of transparency and robustness, this paper proposes a digital watermarking scheme based on techniques of dithered computer generated holograms and DFT domain embedding in order to improve the watermark's transparency and keep its good robustness as well. The dithered hologram is first generated from the binary watermark image and the DFT is performed to the original image. Then, each bit of the continued hologram is embedded in magnitude of the DFT domain at the middle fiequency. The experiment based on this scheme demonstrates that the watermark is both transparent and robust to common digital image processing.