光学图像加密处理毕业设计

摘要

近年来随着计算机技术的飞速发展，网络信息有了广泛得应用，而信息的安全性也越来越受到人们的关注。由于光学信息处理系统的处理速度较高，并且能快速实现相关运算等而深受研究学者的青睐。基于光学系统的图像加密技术在国防安全中具有重要的应用价值。

本文总结了光学加密技术的研究历史和发展现状，介绍传统傅里叶变换的性质以及光学实现方法，并通过Matlab仿真进一步了解傅里叶变换对。同时也针对分数傅里叶的原理和性质，例如可加性、周期性、连续性等进行了描述。并对其光学实现方法进行了介绍。通过分析、讨论分数傅里叶加密、随机相位编码加密，最终在总结相关原理基础之上并进一步提出了基于分数傅里叶变换的双图像加密算法，设计出了相应的光学系统加密装置，并基于实验室的设施状况设计出四个实验主要包括：二维线性系统傅里叶分析、基于傅里叶变换的光学相关器、傅里叶光学在光学图像加密的应用以及光学相关器信息提取实验，通过这些实验对双图像加密理论的可行性进行验证并对其结果加以分析。最终得出双图像加密具有较高的安全性，尤其是编码到相位部位的图像的安全性更高。

关键词：光学图像加密 分数傅里叶变换 双图像加密

Abstract In recent years ,as the rapid development of computer network and communication technology ,the net-information is more widely used .But the information security has attracted much attention. Because of the higher processing speed of the optical information processing system, and it can also quickly achieve correlated operation .All these characteristics are favored by research scholars. Optical system based image encryption technique has important applications in defense security .

The history and current situation of the development of optical encryption technology research is summarized in this paper ,then the traditional Fourier transform method ,characters and its optical realization are also introduced. Besides, the traditional Fourier transform pair are proved by Matlab simulation. The fractional Fourier theory and characters ,such as its additivity, periodicity and continuity are discussed ,then its optical realization is described. Finally a double image encryption algorithm based on fractional Fourier transform is proposed by the mean of analyzing and discussing the fractional Fourier encryption, the random phase encoding encryption,then summarizing their relevant principles. The corresponding optical system encryption devices is also designed. In the end of the paper , four experiments have been designed based on the aboratory facility condition, they include : the analysis of two-dimensional linear systems Fourier , the optical correlator based on Fourier transform, optical image encryption in Fourier Optics and the extraction of an optical correlator information experiments . The feasibility of the theory of double image encryption is proved by the experiments above, besides the result of double image encryption is also analyzed .Finally the conclusion that the double image encryption has higher security, especially the parts of the phase coded image security.

Keywords: optical encryption fractional Fourier transform double image encryption

目录

第1章 绪论 ................................................................ 1

1.1图像加密技术发展现状 ................................................ 1

1.2本课题研究意义与目的 ................................................ 2

1.3论文的主要工作 ...................................................... 2

第2章 光学图像加密理论基础 ................................................ 3

2.1传统光学傅里叶变换 .................................................. 3

2.1.1一维傅里叶变换 ................................................. 3

2.1.2 二维傅里叶变换 ................................................ 3

2.1.3傅里叶变换性质 ................................................. 3

2.1.4 傅里叶变换的光学实现 .......................................... 5

2.2 分数傅里叶变换 ...................................................... 6

2.2.1 Namias型分数傅里叶变换 ........................................ 6

2.2.2 shih型分数傅里叶变换 .......................................... 7

2.2.3 分数傅里叶变换的性质 .......................................... 7

2.2.4 分数傅里叶变换的光学实现 ...................................... 8

2.3联合变换相关识别 .................................................... 8

2.4 本章小结 ........................................................... 10

第3章 基于分数傅里叶变换的图像加密 ....................................... 11

3.1双随机相位编码技术 ................................................. 11

3.2 分数傅里叶加密算法 ................................................. 12

3.3 基于分数傅里叶变换的双图像加密 ..................................... 15

3.4 本章小结 ........................................................... 17

第4章 实验分析 ........................................................... 18

4.1 二维线性系统傅里叶分析 ............................................. 18

4.2 傅里叶变换的光学相关器实验分析 ..................................... 21

4.3傅里叶光学在光学图像加密的应用 ..................................... 23

4.4 相关器信息提取 ..................................................... 24

4.5 本章小结 ........................................................... 26

第5章 安全性讨论 ........................................................ 27

5.1 概述 .................................................................. 27

5.3 本章小结 ........................................................... 29

第6章 总结与展望 ......................................................... 30

6.1 总结 ............................................................... 30

6.2展望 ............................................................... 30

致谢 ...................................................................... 31

参考文献 .................................................................. 32

第1章 绪论

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