基于相移干涉与分数傅里叶变换的纯相位图像加密

Fully phase image encryption based on two-step-only quadrature phase-shifting interferometry and fractional Fourier transform

只有两步的正交相移干涉方法,只需记录两幅干涉图,不需要记录物光波和参考光波的强度信息,就可以再现没有零级像和共轭像的再现像.结合分数傅里叶变换和双随机相位编码,提出一种纯相位光学图像加密技术.解密时,只要获得正确的密钥,经过简单的计算就可以重建清晰的原始图像.模拟实验验证了它的可行性和有效性,并分析了抗裁剪和噪声的鲁棒性以及参考光强度大小对加密解密的影响.

A novel fully phase image encryption technique based on two-step-only quadrature phase-shiftingdigital holography and double random phase encoding in fractional Fourier transform （FRT） domain is proposed, in which only two quadrature phase holograms are required and neither reference-wave intensity nor object-wave intensity measurement is needed. A primary amplitude image is modulated to a fully phase image, and then the fully phase image is encoded into two quadrature digital holograms by using double random-phase masks （RPMS） encoding in the input and fractional Fourier domain transform planes, respectively. The clear primary image can be recovered by simple algorithm with the right keys. The feasibility and validity of this technique has been proved by simulation experiments. And the robustness against occlusion and noise attacks, as well as the effect of the reference wave intensity to image encryption and decryption, has also been investigated.