激光传感过程层析成像技术研究

【作者】 邹旭华；

【导师】 郑莹娜； 李扬；

【作者基本信息】 广东工业大学 ， 测试计量技术及仪器， 2003， 硕士

【摘要】 过程层析成像(Process Tomography，简称PT)技术是使用层析成像方法处理从远端传感器获得的数据，以得到不可达区域内的物场分布信息。本文所探讨的激光PT技术是一种基于透射模式的新型工业过程层析成像技术。它以医学CT技术为背景，将光的吸收和散射原理与由投影重建图像的理论相结合，通过检测被测物质对光调制作用来重建被测物质的空间分布信息。激光PT具有非侵入性、非接触性、无污染性等优点，具有良好的工业应用前景，如可应用于工业过程的成像，生物组织成像，大气污染监测，材料表面探伤等。目前，这项技术是国内外热点研究课题之一。 本文从激光传感层析成像技术的基本理论出发，首先用仿真的方法研究了多种传感器阵列的特点及图像重建算法，然后在自制的实验装置中开展实验研究。主要内容包括： 1．光学PT技术基本原理、发展现状、所面临的关键问题和技术难点； 2．分析了激光传感的光学模型、传感原理以及由投影重建图像的数学模型。 3．传感器阵列设计：对各种传感阵列的特点尤其是其光学敏感场的灵敏度特性作了详细的分析论述； 4．对各种传感结构所对应的多种图像重建算法进行MATLAB仿真研究，分析了各种算法的重建性能。通过对各种图像重建算法的比较与分析，确定各种传感阵列在不同使用环境和要求下的最佳图像重建算法； 5．实验研究：针对激光PT系统的关键问题，在Visual C++6.0环境下实现了软件控制激光器的并、串行激励方式和多路A/D转换和动态图像重建、显示及记录回放等，并得到了实验物场的重建图像以及系统的性能分析结果。针对石英砂颗粒流场进行了大量的实验，并初步得到了石英砂颗粒流场流型的在线识别以及质量流量与光束投影和之间的关系图。从而证实了激光PT技术在气固两相流质量流量计量中的可应用性。更多还原

【Abstract】 Process Tomography involves using tomography imaging method to manipulate data from remote sensor in order to obtain object field distribution information from inaccessible location. And the laser PT technique discussed here is a novel industrial process tomography based on a transilluminated mode, which employs the principles of light absorption and scattering together with image reconstruction from projection to reconstruct the spatial distribution data of measured object via measuring light data modulated by it on the background of medical CT. It, as a non-invasive, non-contact and non-contaminative measurement, shows great advantages in industrial application such as industrial process imaging, biological issues imaging, atmosphere pollution monitoring, material surface crack detecting and so on. At present, this technique becomes one of international hot research items.In this paper, the characteristics of many sensor arrays and the varied algorithms of image reconstruction are studied by means of simulating first, based on the basic principle of laser sense tomography. Next, the experiment researches are brought into execution through self-made experiment equipments, mainly including:1. Fundamental, present development situation, sixty-four-dollar questions and difficulties of Optical PT.2. Analysis of optical model, sensing principle of laser sensors and mathematics model of image reconstruction from projections.3. Several kinds of sensors array have been brought forward and designed. Characters, especially sensitivity characters of their optical sensitivity fields have been also discussed in detail.4. Simulation researches on several image reconstruction algorithms corresponded to sensors structures in MATLAB have been performed to analyze the reconstruction capability of these algorithms. The best algorithm in various desires and conditions are decided through the comparison among the algorithms.5. In experiment research, control of parallel and serial drive mode of laser sensors,multiplex A/D transform and dynamic image reconstruction, display and saving for replaying are realized with soft aiming at the key questions of laser PT. And reconstructed images and analysis results of system capability are successfully obtained. Furthermore, the identify on line of flow model and relationship of quality flux and light projections have been elementarily found through plenty of experiments on quartz particles flow fields. This approved laser PT is applicable to flow quantity measurement in two-phase flow of gas and solid.更多还原