针对联合变换相关器(JTC)多图像加密系统对于加、解密灰度图像时, 解密图像质量不理想的问题, 利用前期提出的一种灰度图像二值编码方法, 设计了一种基于灰度图像二值编码的JTC多图像加密系统。该系统将灰度多图像的加、解密问题转化为二值多图像的加、解密问题, 可有效抑制加、解密过程中产生的非饱和噪音, 提高图像解密质量。仿真结果表明, 相同条件下在基于螺旋相位模板拓扑荷数复用的JTC多图像加密系统中使用灰度图像的二值编码图像进行加、解密相对于直接加、解密灰度图像, 其相关系数值有显著提升, 再使用中值滤波抑制解密图像中的饱和噪音, 可进一步提高解密图像质量。

For current multi-image encryption system of joint transform correlator (JTC), the quality of decryption image is not good when encrypting or decrypting gray image, thus in this paper, a JTC multi-image encryption system based on binary coding for gray images is designed. The system converts the problem of encrypting gray multi-image into the problem of encrypting binary multi-image, which can effectively suppress the unsaturated noise generated during the process of encryption and improve the quality of decrypted images. The simulation results show that the correlation coefficent of the decryption image using the binary coding image of the gray image is significantly improved in the JTC multi-image encryption system based on spiral phase masks topological charge number multiplexing. Then the quality of the decrypted image can be further improved by using the median filtering to suppress the saturation noise in the decrypted image.