Encryption/Decryption with Optical Transform

In this chapter, the methods of image encryption and decryption based on optical transformation are introduced. The extended fractional Fourier transform is constructed by designing an eccentric lens group, and is used in the image encryption system. By using the Fresnel diffraction model, an iterative phase recovery algorithm is constructed, and a color image hiding method and optical system are introduced. A parallel phase retreival technique in gyrator transform domain is constructed, and is applied to construct an image decryption system.