基于全息技术的光学加密系统实值编码

Real-value Encryption for Optical Security System Based on Holography

提出一种基于全息技术用于光学图像加密的实值编码方法.待编码的数字图像与一个大小相同、灰度值为零的图像组成一幅新的图像,然后与一个随机相位掩膜一起通过光学透镜作傅里叶变换,取变换结果的实部作为编码输出图像·利用全息记录的方法解码,即编码输出图像和随机相位掩膜的傅里叶变换相加通过光学透镜作傅里叶反变换,记录反变换的光强分布,再通过非线性变换或灰度变换的方法可以恢复原图像·

A real-value encryption and decryption method is proposed for the optical image security system based on holography. A full-phase image to be encrypted stands side by side a black image in the same size. They together with a random phase mask are Fourier transformed and real part of the result is used as an encrypted image. The addition of encrypted image and the Fourier transformed of the random phase is inverse-Fourier transformed. The intensity values of inverse-Fourier transformed image is adjusted. It gives the exact original image.