级联迭代傅里叶变换算法在光学安全中的应用英文文献及翻译（可编辑）.docVIP

级联迭代傅里叶变换算法在光学安全中的应用英文文献及翻译 A cascaded iterative Fourier transform algorithm for optical security applications Abstract:A cascaded iterative Fourier transform CIFT algorithm is presented for optical security applications. Two phase-masks are designed and located in the input and the Fourier domains of a 4-f correlator respectively, in order to implement the optical encryption or authenticity verification. Compared with previous methods, the proposed algorithm employs an improved searching strategy: modifying the phase-distributions of both masks synchronously as well as enlarging the searching space. Computer simulations show that the algorithm results in much faster convergence and better image quality for the recovered image. Each of these masks is assigned to different person. Therefore, the decrypted image can be obtained only when all these masks are under authorization. This key-assignment strategy may reduce the risk of being intruded. Key words: Optical security ? optical encryption ? cascaded iterative Fourier transform algorithm 1. Introduction Optical techniques have shown great potential in the field of information security applications. Recently Réfrégier and Javidi proposed a novel double-random-phase encoding technique, which encodes a primary image into a stationary white noise. This technique was also used to encrypt information in the fractional Fourier domain and to store encrypted information holographically. Phase encoding techniques were also proposed for optical authenticity verification Wang et al and Li et al proposed another method for optical encryption and authenticity verification. Unlike the techniques mentioned above, this method encrypts information completely into a phase mask, which is located in either the input or the Fourier domain of a 4-f correlator. For instance, given the predefinitions of a significant image fx, y as the desired output and a phase-distribution expjbu, v in the Fourier domain,