用于光学图象加密的分数傅里叶变换双相位编码

作者提出了一种用于图象加密的基于分数傅里叶变换的双相位编码技术.该方法由于密钥比传统的编码技术增加两重,因而其安全性有所改进.

OPTICAL IMAGE ENCRYPTION BASED ON DOUBLE PHASE ENCODING WITH FRACTIONAL FOURIER TRANSFORM

A fractional Fourier domain double phase encoding method is proposed for the optical image encryption system.The encryption technique adopts two stages of fractional Fourier transforms with the conventional random phase encoding in both of the original image plane and the fractional Fourier domain Numerical simulations show that the proposed technique is as efficient as the conventional Fourier domain random phase encoding.However,with the additional degrees of freedom provided by the fractional Fourier transform,the numbers of security keys can be increased from two to four.That makes the encrypted image more difficult to be decrypted by an unauthorized person.