To overcome the disadvantage of the symmetry of input and frequency planes in the previous optical image encoding systems,an improved encryption method is proposed.

• 针对以往光学图像加密系统中输入面和频谱面对称性的缺点,在不增加系统元件的基础上,利用球面波照射不对称非标准傅里叶变换系统进行图像加密。