以分数小波变换为基本理论依据,介绍了一种基于分数小波变换的双随机相位光学图像加密技术,丰富了光学图像加密的方法。该方法通过研究分数小波变换和随机相位,得到了一种多密钥的选择性光学图像加密系统。其特点在于利用分数小波变换多层次分解的优势,结合双随机相位编码,不仅增大了密钥空间,增加了安全性,而且能够实现选择性加密,使加密技术变得更加灵活和多样。通过仿真验证了该方案,可实现多密钥加密,并结合仿真结果,理论分析了该方案的加密效果、密钥的安全性和选择性加密的优良特性。研究可知,该方案是一种新的有效的光学图像加密方案。

An optical image encryption method based on fractional wavelet transform with double random phases is introduced, adding new options for the optical encryption method. By combining random phases with fractional wavelet transform, the selective optical image encryption system with a multiple-key is obtained. The new method employs the multi-level decomposition advantages of fractional wavelet transform as well as the double random phase encoding so that it not only expands the key space and improves security, but also realizes selective-encryption and becomes flexible. The method is verified by simulation, which demonstrates to be able to realize multi- keys encryption. Moreover, such fine properties as selective-encryption, the security of keys and encrypted results are also analyzed. Research has proved the method to be a new and effective optical encryption choice.