激光莫尔干涉谱投影信息提取  

Extracting Projections from Laser Moire Interference Spectra

作　　者：宋一中[1,2] 赵志敏[1] 贺安之[3] 

机构地区：[1]南京航空航天大学理学院物理系,江苏南京210016 [2]德州学院物理系,山东德州253000 [3]南京理工大学理学院信息物理与工程系,江苏南京210094

出　　处：《光谱学与光谱分析》2009年第1期66-69,共4页Spectroscopy and Spectral Analysis

基　　金：中国博士后科学基金项目(20060400930);江苏省博士后基金项目(0602040B);国家自然科学基金项目(10404022)资助

摘　　要：分析了真实火箭喷焰的激光莫尔干涉谱,并提取其投影信息,重建了密度场。使用自制的大口径、高灵敏度莫尔偏折仪采集真实火箭喷焰的莫尔条纹图;采用傅里叶变换对莫尔条纹展开技术处理,获得了莫尔条纹的相位分布。根据莫尔条纹边缘提取背景,进一步获得背景相位分布。变形莫尔条纹的形变量通过求相位差获得,进一步提取轴向任意截面的投影信息。应用基于偏折投影的"简单自相关代数迭代重建算法(SSART)"层析流场。等间隔取8个方向的投影进行迭代,重建了截面密度分布图。结果发现,根据火箭喷焰的莫尔条纹,采用傅里叶变换相位展开技术,可以方便地提取任意截面的投影信息。应用SSART技术可以重建截面密度分布。因此,基于偏折投影的"SSART"算法是一种优良的非线性偏折层析重建算法。Laser Moire Interference spectra of rocket exhausted plumes were analyzed.Projections for reconstruction were figured out,and air density distribution was reconstructed.Moire deflectograms of the plumes were produced and captured with a home-made,wide-range,high-sensitivity Moire deflectometer.Moire interference spectra were processed by phase unwrapping technique with Fourier transform,so the space phase distribution of Moire deflectograms was extracted.The background was worked out based on the margin of the Moire deflectograms,and so was the space phase distribution of the background.The phase shift distribution of distorted Moire interference spectra could easily be obtained by calculating the difference between the two space phase distributions.The relative projections could be extracted from the phase shift distribution.The air density distribution of the plumes was calculated by simple self-correlative algebraic reconstruction technique（SSART） based on deflected angles for projections.Eight projections with equal direction interval of 20 degree were used for reconstructing the air density distribution of a plume section.As a result,with phase unwrapping technique based on Fourier transform,any cross section projection could conveniently be worked out from the Moiré deflectogram of rocket exhausted plumes.The air density distribution of the cross section could be reconstructed by SSART.So,SSART with deflected angle for projection is a kind of super nonlinear deflection tomography.

关 键 词：莫尔条纹 傅里叶变换 投影 重建 层析 

分 类 号：O361[理学—流体力学]