QQ客服 官方微博 反馈留言

题名	湍流介质中鬼成像研究
作者	张鹏黎
学位类别	博士
答辩日期	2010
授予单位	中国科学院上海光学精密机械研究所
导师	韩申生
关键词	鬼成像 关联成像 相位屏 大气湍流
其他题名	Ghost Imaging through Turbulent media
中文摘要	鬼成像又称双光子成像或关联成像，是一种利用二阶强度关联获取物体信息的探测技术。自从上世纪九十年代中期该技术第一次实验证明以来，经过十多年的发展，鬼成像在理论和实验上逐步成熟。最近，更多的关注集中在如何将鬼成像技术实用化，以突破传统成像技术的局限性。本文提出将鬼成像应用到远距离空间遥感探测中，分析大气湍流对鬼成像系统的影响。通过数值模拟，进一步探讨通过大气湍流鬼成像的具体表现。论文内容安排如下： 第1章首先阐述有关远距离空间遥感探测领域的背景知识，以及常见的消除湍流效应的技术方法（如散斑成像和自适应光学等）。介绍当前国际上在空间探测领域的研究现状。为降低湍流影响，提出通过大气湍流的鬼成像方案。 第2章回顾大气湍流理论的发展，引入湍流理论模型和描述湍流统计特性的物理参量（包括大气折射率结构常数和功率谱函数）。详细分析湍流效应对光在大气中传输影响。我们讨论构造随机相位屏方法，该相位屏可用于模拟湍流导致的位相扰动。随后，通过考察高斯光束在大气中传播行为验证相位屏模型的可靠性。 第3章从介绍鬼成像原理和热光统计特性开始，在统计光学框架内，建立鬼成像二维数值仿真程序，包括热光场动态变化，光场传输以及图像恢复。详细讨论数值模拟中应注意的问题（包括网格间距和独立子光源数的选取）。 第4章，我们从光源发射、光路排布、信号探测等方面详细阐述通过大气湍流鬼成像方案。基于扩展的惠更斯-费涅尔积分公式，分析湍流效应对鬼成像系统的影响。利用数值模拟程序，研究大气环境中鬼成像系统的具体表现。 第5章，我们探索提高鬼成像图像质量的方法。通过点对点的强度关联可以有效的提高图像分辨率。在鬼成像系统中应用平衡零拍探测，可是实现对纯位相物体的成像。粗糙物体的鬼成像和噪声问题也进行了相关研究。 最后一部分总结本文的主要内容，展望鬼成像在临床诊断和X光成像领域的应用前景。并给出下一步工作计划安排。
英文摘要	Ghost imaging，also called two-photo imaging or correlated imaging，is an unique technique that extracts the information of an object by measuring the correlation of two fields. Since its experimental realization in the mid 1990s, ghost imaging has developed very well for the past decade. Recently, more attentions have been focused on how to apply this technique to practical applications to overcome the limits in conventional optical systems. Here, we proposed a scheme of remote sensing by taking advantage of ghost imaging principle and derived analytical expressions describing turbulence effects on image resolutions. The performance of ghost imaging through atmospheric turbulence was investigated by numerical simulations. The paper is organized as follows. Chapter 1 begins with relevant background material in the field of space remote sensing imaging in the atmosphere, and introduces some techniques (such as speckle imaging and adaptive optics) for overcoming turbulence effects. And then the latest researches about imaging through turbulence are presented. To reduce the influence of turbulence, ghost imaging through turbulence has been proposed. In Chapter 2, an overview of the development of turbulence theory is provided. Some parameters characterizing turbulence, including the structure constant of the index of refraction fluctuations and spatial power spectral density, have been introduced. We analyze how turbulence-induced perturbations affect the propagation of light in details. The method for creating random phase screens that simulates turbulence-induced phase aberration is discussed. Subsequently, we validated the model of phase screens by studding the behaviors of the propagation of Gaussian beam in the atmosphere. Chapter 3 presents the basic principle of ghost imaging firstly. The statistical properties of thermal light are also presented. On the framework of statistical optics, we models ghost imaging, including the dynamic process of thermal variation, the propagation of optical fields and the reconstruction of images. Some issues concerning numerical simulations are discussed. In Chapter 4, we report the scheme of ghost imaging through atmospheric turbulence, including the fields of the launcher of the source、the propagation of light fields、the detection of reflection signal and so on. Based on the extended Huygens-Fresnel integral, the Analytical calculations about ghost imaging through turbulence have been presented. The performance of ghost imaging in the atmosphere is investigated through simulations. In Chapter 5, we exploit some approaches to improve qualities of ghost images. The image resolution can be enhanced by the point-to-point intensity correlation. We apply balanced homodyne detection to ghost imaging systems to detect phase-only object. Ghost imaging for the object with rough surface and the noise problem have been studied here. At last, the paper is summarized in Chapter 6, and we prospect potential applications of ghost imaging in clinical diagnosis and X-ray imaging. The plan and arrangement have been made.
语种	中文
内容类型	学位论文
源URL	[http://ir.siom.ac.cn/handle/181231/15637]
专题	上海光学精密机械研究所_学位论文
推荐引用方式 GB/T 7714	张鹏黎. 湍流介质中鬼成像研究[D]. 中国科学院上海光学精密机械研究所. 2010.

个性服务

查看访问统计

相关权益政策

暂无数据

收藏/分享

除非特别说明，本系统中所有内容都受版权保护，并保留所有权利。