Gyrator变换全息图及其在图像加密中的应用

提出了gyrator变换全息图,利用gyrator变换快速算法模拟实现了gyrator变换全息图的产生和再现,并研究了基于相移数字全息的gyrator变换全息图.在此基础上提出了采用正弦相位光栅实现光学图像加密的新方法.该方法利用gyrator变换在相空间的旋转特性,将gyrator变换的角度、光栅的频率及光栅的旋转角度作为加密密钥,并利用两个或两个以上的gyrator变换系统的级联实现图像加密,增加了系统的安全性.依据相移数字全息进行的两个gyrator变换系统级联的仿真实验验证了该方法的可行性、有效性及其良好的安全性能.

Gyrator Transform Hologram and Its Application in Image Encryption

The gyrator transform hologram is proposed. The generation and the reconstruction of the gyrator transform hologram are simulated by using the fast algorithm for computing the gyrator transform. This new type hologram based on phase-shifting digital hologram is also studied. A novel method is proposed for optical image encryption by using sinusoidal phase gratings based on the methods mentioned above. In this proposal method, the angle of gyrator transform, the frequency and the rotation angle of the gratings are regarded as the encryption keys according to the rotation properties of the gyrator transform in the phase space. Two or more cascaded gyrator transform systems are applied to realize the image encryption. The simulation experiments are performed with two cascaded gyrator transform systems on the basis of the phase-shifting digital hologram. The results confirm the feasibility, validity and the secure performance of the proposal method.