Optical Image Encryption Method for Computational Ghost Imaging Using Phase Iterative Algorithm

Abstract

The invention discloses an optical image encryption method for calculating ghost imaging by using a phase iterative algorithm, which comprises the following steps of: 1) performing collimation illumination on a laser beam, and sequentially inputting a group of different random phase masks into a spatial light modulator; wherein the wave is modulated by a pure phase mask, and the generated random speckle pattern passes through the object at the axial distance from the plane of the spatial light modulator; 2) wherein a transmission function T ([mu]m, v) of the object, Ii ([mu]m, v) = | Ei ([mu]m, v) | 2 being a speckle pattern, Ei ([mu]m, v) being a free space propagation field of the pure phase mask and (mu, v) representing lateral coordinates of the object plane; performing, for each purephase mask embedded in the spatial light modulator, by using Fresnel diffraction; and 3) correlating the intensity distribution collected by the barrel detector with the speckle pattern derived from the known pure phase mask. The method provided by the invention is simple and easy to implement and high in accuracy.

Description

technical field [0001] The invention belongs to the technical field of image security, and relates to an optical image encryption method using a phase iterative algorithm for computing ghost imaging. Background technique [0002] Ghost imaging, known as correlated photon imaging, is an interesting optical imaging technique that allows the reconstruction of objects by using intensity correlations. So far, a large number of new structures and algorithms for ghost imaging have been developed. Based on the famous image encryption structure of double random phase encoding, many optical technologies have been widely used in the field of information security due to its high-speed parallel processing and multi-dimensional capabilities. It can be found that there are two main disadvantages in the ghost imaging process. First, there is a need to further improve the quality of reconstructed images of measured intensities collected by single-pixel bucket detectors. Because the random...

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Problems solved by technology

Second, it is very inconvenient in terms of storage and transmission when a large number of pure phase masks are considered as secret keys

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