Evaluation of virtual source beam configurations for rapid tomographic reconstruction of gas and vapor concentrations in workplaces.
Evaluation of virtual source beam configurations for rapid tomographic reconstruction of gas and vapor concentrations in workplaces.
复制标题
评估虚拟源光束配置，以快速重建工作场所气体和蒸汽浓度。
DOI：
10.1080/10473289.1997.10463687
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发表时间：
1997
期刊：
影响因子：
--
通讯作者：
Levine,SP
中科院分区：
文献类型：
--
作者：
Park,DY;Yost,MG;Levine,SP
来自开放路径傅立叶变换红外 (OP-FTIR) 光谱仪的光束路径平均数据可用于利用计算机断层扫描 (CT) 技术重建工作场所和环境中气体和蒸汽污染物的二维浓度图。然而，由于过去需要多源和检测器单元来产生足够数量的交叉光束路径以重建浓度图，因此出现了实际限制。这种系统要应用于实际的现场监测情况，费用和难度都很大。能够快速移动光束的单站 OP-FTIR 系统可以消除这一缺陷。代替许多源和探测器单元，虚拟源布置被提出使用多个平面镜和后向反射器来获得相交的折叠光束路径。使用54个平面镜和四个后向反射器或沿着典型的24-x 21-英尺测试室的周壁安装的54个平面镜和56个后向反射器来测试为单光束可操纵FTIR系统生成的三个虚拟源光束配置。使用根据在测试室中通过实验测量的示踪气体浓度分布创建的浓度图对虚拟源 CT 配置进行数值评估。根据测试图和光束配置计算合成光束路径积分数据。不同光束配置的计算机模拟用于确定光束几何形状的影响。评估了噪声和峰值降低伪影的影响。断层扫描重建策略的性能作为浓度和浓度梯度的函数进行了测试。
Beam path average data from an Open Path Fourier Transform Infrared (OP-FTIR) spectrometer can be used to reconstruct two-dimensional concentration maps of the gas and vapor contaminants in workplaces and the environment using computed tomographic (CT) techniques. However, a practical limitation arises because in the past, multiple-source and detector units were required to produce a sufficient number of intersecting beam paths in order to reconstruct concentration maps. Such a system can be applied to actual field monitoring situations only with great expense and difficulty. A single monostatic OP-FTIR system capable of rapid beam movement can eliminate this deficiency. Instead of many source and detector units, a virtual source arrangement has been proposed using a number of flat mirrors and retroreflectors to obtain intersecting folded beam paths.Three virtual source beam configurations generated for a single-beam steerable FTIR system were tested using 54 flat mirrors and four retroreflectors or 54 flat mirrors and 56 retroreflectors mounted along the perimeter walls of a typical 24- x 21-ft test room. The virtual source CT configurations were numerically evaluated using concentration maps created from tracer gas concentration distributions measured experimentally in a test chamber. Synthetic beam path integral data were calculated from the test maps and beam configurations. Computer simulations of different beam configurations were used to determine the effects of beam geometry. The effects of noise and peak-reducing artifacts were evaluated. The performance of the tomographic reconstruction strategy was tested as a function of concentration and concentration gradients.