中文摘要：

为了提高光学加密系统的传输效率和安全性，提出了一种多二值图像光学加密技术。该方法加密时采用数字方法和光学方法联合实现，解密过程可采用纯光学方法实现。加密时，首先将待加密图像乘以不同密钥进行频谱扩展，再进行算术叠加生成复合图像。然后将复合图像置于联合变换相关器的输入面上进行光学加密。解密时，需要在频率域利用光阑从复合图像中提取出每一幅原始图像。理论分析和计算机仿真表明，该多二值图像光学加密技术系统结构简单，图像复用容量巨大，具有较高的安全性。

英文摘要：

In order to improve the efficiency of transmission and security of the optical encryption system, a multiple binary images optical encryption technology is proposed. This technology uses digital method and optical method in the encryption process, and pure optical method in the decryption process. In the encryption process, each original image’s spectrum is spread by multiplying with a encryption key and then all the images are added together to generate a composite image. The composite image is put on the input plane of the joint transform correlator for optical encryption. In the decryption process, each of the original images needs to be extracted from the composite image by an aperture in the frequency domain. Through theoretical analysis and computer simulation, the multiple binary images optical encryption technology system is very simple, and it has high image multiplexing capacity and security.