摘要莫尔体层析技术（Moiré Volume Computerized Tomography）是将光学计算层析技术与光学莫尔技术相结合的一种用于三维相位场显示与重建的技术。由于具有非接触性、测量范围广，对环境稳定性要求低等特点，因而在气动流场诊断中具有重要应用价值。64389

在莫尔体层析技术中，投影图像中所包含相位物体的信息特性及信息提取方法一直是影响后续三维精确定量CT重建的关键技术难题。针对莫尔层析投影光路的相位提取问题，本文从标量衍射理论出发，分别对双直线光栅和双正交光栅的莫尔层析光路进行了研究。首先，通过分析，获得两种光路对应的莫尔条纹图的解析表达式，并分析了不同衍射频谱对应的莫尔条纹图之间的空间相移特性。其次，在此基础上，设计了能同时获得多幅空间相移图像的正交光栅莫尔层析投影光路，并进行了分析。最后，采用两步相移算法对双直线光栅形成的两幅空间相移图像进行了相位提取的数值模拟。

毕业论文关键词  莫尔层析 莫尔条纹图 空间相移 两步相移算法

 毕业设计说明书（论文）外文摘要

Title  Moiré Volume Computerized Tomography based on double cross gratings 

Abstract Moiré Volume Computerized Tomography is a technique for 3D phase field display and reconstruction, which is combined of optical computed tomography technology and optical Moire technique. Because of its non-contact measurement, strong anti-disturbing capacity, and wide measurement range, it has important application value in the aerodynamic flow field diagnosis.

In the Moiré Volume Computerized Tomography, characteristics of information and the extraction method of phase object are the impact key technical problem of subsequent 3D CT reconstruction. Aimed at the problem of extraction phase Moore tomography projection.  This article started from the scalar diffraction theory, studied the optical Moore tomography from double gratings and double cross gratings.Firstly, through analysis, obtained analytical expressions of the moire fringe pattern correspond to two optical paths. Secondly, on the basis of this, designed the path which can obtain a few of spatial phase shift images at the same time.Finally, used the two-step phase-shifting algorithm to simulate two Spatial phase shift diagram based on the double gratings.

Keywords  Moiré Computerized Tomography  Moiré fringe  spatial phase shift  Two step phase shifting algorithm

目 录

1  绪论 1

1.1  计算机层析技术概述 1

1.2  光学层析技术概述 1

1.2.1  光学发射CT(ECT) 1

1.2.2  光学干涉CT 2

1.2.3  光学莫尔CT 3

1.3  莫尔CT的投影数据提取 3

1.3.1  基于灰度的条纹跟踪方法 4

1.3.2  傅里叶变换法 4

1.3.3  相移方法 4

1.4  本文的研究内容 5

2  双光栅空间相移特性研究 6

2.1  双光栅莫尔层析图像形成分析 6

2.2  无相位物体的莫尔条纹图 9

2.3  有相位物体的莫尔条纹图 12

2.3.1  莫尔条纹图