中文摘要 莫尔体层析技术是将莫尔条纹术与三文光学层析技术结合的新兴方向。该技术主要应用于复杂流场的诊断与测试,可以真实恢复被测场的三文分布信息。本论文的研究主要基于平行投影下的三文层析技术理论,用圆光栅提取出投影波前关于径向的导数,为精确的三文重建奠定基础。本文主要完成了两项工作:首先基于标量衍射理论推导了圆光栅莫尔条纹的精确解析表达式,并且发现莫尔条纹中包含了投影波前的一阶径向导数;其次,研究了从莫尔条纹中进行相位提取的方法, 分别利用改进的傅里叶变换方法(FT)以及基于局部空间频率的方法(FSD)提取相位,两种方法都能比较精确地从投影莫尔条纹中提取出投影波前在径向的一阶导数。 6650
关键词 圆光栅 莫尔条纹 三文计算层析 相位提取
毕业设计说明书(论文)外文摘要
Title Study on the projection characteristic of moire volume tomography using circular gratins
Abstract
Moiré volume computerized tomography is a new-born technique that combines
moiré tomography and 3-D optical computerized tomography. It is mainly used
in areas such as complex flow visualization and measurement and can restore
the 3-D distribution of the tested field. Based on parallel projection of
3-D tomography theory, second radial order partial derivatives of
projection wave front is dealt with, which lays foundation on 3-D exact
reconstruction work. The main work is described as follows: the exact
expression of circular gratings’ moiré fringes is given with the help of
scalar diffraction theory; using improved Fourier-transform method(FT)
and local frequency sequence demodulation method(FSD), the first radial
order derivative of the projection wave front can be successfully obtained
from circular gratings’ moiré fringes.
Keywords Circular grating moiré fringe
3-D computerized tomography Phase extraction
目 次