基于相位恢复算法的二值全息数字水印技术

摘要

为了减小全息水印技术嵌入的信息量，基于信息光学理论提出一种新的数字水印方法。采用相位恢复算法将水印信息编码为虚拟入射物波的纯相位函数，同参考光波相干，得到对比度很高的全息图，再将该全息图二值化。比传统傅里叶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。在离散余弦变换域嵌入二值全息图，提取时实现了水印的盲检测。仿真对比实验证明，该方法对与传统二值全息方法相比对多种常规图像处理，水印的鲁棒性得到明显提高。%A new approach of digital watermark based on information optic theory is proposed to reduce the embedded infor-mation of holographic watermark. The watermark information is transformed into pure phase function by phase retrieval algorithm which interferes with reference light wave to form high contrast Fourier hologram and then binarize it. This binary hologram loses much less information than the traditional Fourier binary hologram,and can improve the quality of reconstructed images greatly. Binary hologram is embedded into discrete cosine transform(DCT)domain of host image,and the blind detection of the water-mark is realized by the watermark extraction. The simulation and contrastive results show that the algorithm has better robustness to many kinds of common image processing compared with traditional methods.