基于二值约束和相位恢复算法的计算全息水印

为了提高全息水印图的对比度,增强水印鲁棒性,基于信息光学理论提出一种新的计算全息水印方法。首先将计算全息图进行再现,去除相位并保留振幅信息;然后利用相位恢复的方法,用二值约束条件的相位信息对保留的振幅进行调制,经过反复迭代最终得到相位恢复的灰度全息图。通过仿真实验证明了该方法在JPEG压缩、剪切、滤波、加噪等几种常规攻击下有很好的鲁棒性。上述方法不仅提高了全息图的抗干扰性能,也比对计算全息图二值化丢失的信息量更少,大大提高了再现像的质量。可以有效地运用于一些数字产品的版权保护中。

Computer-generated holographic watermark based on binary constraint and phase retrieval algorithm

Based on information optic theory,a method of computer generated holographic watermark is proposed to im-prove the contrast of hologram watermark and enhance robustness of watermark. The computer generated hologram（CGH）is re-produced,and then the phase is wiped off,but amplitude is reserved. The reserved amplitude is modulated with phase recon-structing method and phase information under binary restrant condition. The gray hologram is finally obtained with the phase re-trieval algorithm and the repeat iteration. The simulation results show that the proposed method has high robustness under con-ventional attacks of JPEG compression,shearing,filtering,noising,etc. This method can not only improve the anti-jamming performance of hologram and the quality of reconstructed image,reduce information loss,but also can be used in copyright pro-tection of digital products.