为比较光学图像加密中随机模板的特性，分别利用随机相位模板和随机振幅模板对几种典型的光学图像加密系统进行了光学图像加密的数值模拟和加密效果分析。模拟结果表明，将随机振幅模板用于基于光学傅里叶变换的双随机模板图像加密系统时，原始图像和加密图像的相关系数大于05，不能有效加密原始图。但将其用于基于菲涅耳变换全息的光学图像加密系统时，原始图像和加密图像的相关系数趋于0，可获得与使用随机相位模板时非常接近的加密效果。

To compare the properties of random mask in the optical image encryption, optical image encryption was stimulated and image encryption effects were analyzed using random phase mask and random amplitude mask in the several typical optical image encryption systems. The stimulation result shows that the correlation coefficient between original image and encryption image is bigger than 05 when random amplitude mask is used in double random mask optical encryption system based on optical Fourier transform and the original image can not be encrypted effectively. But the correlation coefficient between original image and encryption image approaches 0 when random amplitude mask is used in optical encryption system based on optical Fourier transform holography and the encryption effect is similar to one when random phase mask is used.