基于四步相移法实现全息的信息隐藏

针对光信息安全方向,提出了快速卷积算、四步相移法和信息隐藏相结合的一种新的全息图像重建的方法。该方法首先对图像进行菲涅尔衍射积分的快速卷积算法,四步相移方法产生4个数字全息图,将其中一个全息图像(密钥)加载于经过低通滤波器处理后的宿主图像的频谱中,完成了数字水印的嵌入过程。接着对嵌入数字水印后的载体数据进行逆傅里叶变换可提取出数字水印信息,即其中一个全息图。再接着根据四步相移法得到的另外三个全息图(公钥)得到重建全息图像需要的物光复振幅,最后利用菲涅尔衍射积分的快速卷积反变换算法,得到想要的图像。这种基于快速卷积算法和四步相移算法对全息图像的重建质量有了提高,数字水印对全息图像的加密提高了对信息的传输的安全性。

Holographic Information Hiding Based on the Four-step Phase Shifting Method

In this paper, a numerical calculation of the Fresnel integral transform is carried out, and then applied four-step phase shifting method to obtain four holographic images.We can randomly choose a holographic image embedded in the host (vector) image in airspace, which achieves a holographic information hiding of watermark image, and the remaining three watermark holograms stored as public key.For the host image of containing the watermarking information to do the inverse operation of the watermarking embedding process, we can extract the watermarking information hologram.Used the extracted watermarking hologram and others three public holograms we can reconstruct the watermarking image by four-step phase shifting hologram reconstruction.The paper also gives a numerical example, the results show that under the premise which is almost without affecting the visual quality of the host image, the extracted image with high resolution, obtained very good effect of information hiding.The method is a based on information hiding and encryption method of optical holographic information, which has many advantages, such as multidimensional, high-capacity, high robustness and difficult to crack, etc.It is a method of having a potential value.