Image encryption method based on vortex beams and phase recovery algorithm

A technology of vortex beam and phase recovery, which is applied in the field of information security and can solve problems that need to be developed

Inactive Publication Date: 2015-02-25
ZHEJIANG FORESTRY UNIVERSITY
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Most of the image encryption methods based on the phase recovery algorithm proposed so far use parallel coherent light as the incident light wave of the optical decryption system, and the research on the application of different incident light waves in the image encryption system still needs to be carried out

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  • Image encryption method based on vortex beams and phase recovery algorithm
  • Image encryption method based on vortex beams and phase recovery algorithm
  • Image encryption method based on vortex beams and phase recovery algorithm

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Embodiment Construction

[0038] The present invention is described in detail below in conjunction with embodiment and with reference to accompanying drawing: the encryption process of the method for the present invention can pass through figure 1 The phase recovery algorithm shown is implemented, and the decryption process is passed through figure 2 The photoelectric hybrid system shown is completed. A spatial light modulator (spatial light modulator, SLM) has the ability to display complex amplitude signals. Image encryption process (such as figure 1 shown) in the following steps:

[0039] (i) Function U 0 (x 0 ,y 0 )=exp[ilφ(x 0 ,y 0 )] represents a helical phase plate, where φ represents the space azimuth, l is the topological charge, (x 0 ,y 0 ) represents the coordinates of the plane where the spiral phase plate is located, and when x 0 = 0, φ = 0, the unit amplitude parallel coherent light with wavelength λ is incident on the spiral phase plate to generate a vortex beam, then the di...

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Abstract

Provided is an image encryption method based on vortex beams and a phase recovery algorithm. The method includes the following two major steps of encryption and decryption, wherein in the encryption step, an image to be encrypted is encrypted into a phase plate on the basis of the phase recovery algorithm of iteration Fresnel transform under irradiation of the vortex beams, and the topological charge number, the light wave wavelength and the diffraction distance, used in iteration calculation of the phase recovery algorithm, of a spiral phase plate all become secret keys required in the decryption process; in the decryption step, the spiral phase plate and the phase plate obtained in the encryption process are correctly placed in an optical decryption system according to the parameter, namely, the diffraction distance, and then the decrypted image can be obtained on an output face of the system. The encryption method has the advantages that the decryption light path is simple in structure, the number of data to be transmitted and stored is small, and the security of the system is high.

Description

【Technical field】 [0001] The invention relates to the technical field of information security, in particular to an image encryption method. 【Background technique】 [0002] The phase recovery algorithm is a method to determine the phase distribution of the light field through the measurable light field intensity, among which the most widely used are GS algorithm, HIO algorithm, YG algorithm and POCS algorithm. Phase recovery algorithm has been widely used in electron microscopy, wavefront reconstruction, surface shape detection and other fields. In 1996, Wang et al. used phase recovery algorithm to achieve pure phase encoding of images. In the same year, Johnson and Brasher used the phase recovery algorithm to encrypt the image information into two phase plates, and the decryption of the image was completed through the classic double random phase encryption system. The dual random phase encryption system was proposed by two experts, Refregier and Javidi of the University of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): G06T1/00
Inventor 汪小刚周国泉戴朝卿
Owner ZHEJIANG FORESTRY UNIVERSITY
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