基于PXI总线技术的电阻抗成像系统研究
发布时间：2018-08-07 08:27
【摘要】：电阻抗断层成像(Electrical Impedance Tomography,EIT)技术,作为继形态、结构成像之后,出现的一种新兴的功能性成像技术。相比于传统的CT成像技术,电阻抗断层成像技术具有非侵入性、无损害检测,功能性成像,结构简单,使用方便,成像速度快,可多次测量、重复使用,便于进行长期连续监护等优点。传统的电阻抗成像系统是按照英国谢菲尔德大学最早提出的相邻激励和相邻测量的工作模式设计和实现的,但是相邻测量的模式存在着相同激励情况下测量数据之间存在相位差的缺陷。本研究的重点工作即是研究设计同步测量的电阻抗成像系统。论文主要围绕以下三方面进行阐述。一、基于PXI+FPGA的异步测量EIT系统设计:1.在实验室原有的FPGA电阻抗成像系统基础上,将数据采集部分改进为基于PXI总线的数据采集卡。搭建由被测对象,数据采集系统和成像计算机三部分组成的基于PXI+FPGA的异步测量EIT系统硬件平台并完成调试。2.采用LabVIEW和MATLAB语言开发了上述系统的软件程序。3.在物理实验水槽上进行不同尺寸目标的静态成像实验,并且利用图形重建算法实现了图像重构。二、基于PXI总线的同步测量EIT系统设计:1.搭建由被测对象、激励源模块、切换开关模块、数据采集模块、控制器模块和上位计算机组成的基于PXI总线的同步测量EIT系统硬件平台并完成调试。2.采用LabVIEW和LabVIEW FPGA软件平台,开发并完善了同步测量EIT系统软件。3.对系统性能进行测试。实验结果表明,系统的性能达到成像要求。4.对不同的目标物体进行静态实验和动态实验,并经过图像重建算法进行图像重构,成像结果经过评价指标衡量,比较理想。5.对比了异步测量与同步测量的成像结果。三、基于PXI总线的同步测量EIT系统的肺呼吸过程图像重构:1.将EIT系统用于人体呼吸过程的成像,最重要的就是对电极进行改造。论文针对市场上常用的银/氯化银心电电极进行对比与选择。对选定的电极采用阻抗分析仪进行阻抗特性测试,测试结果证明其特性满足电阻抗测量要求。2.对人体的肺呼吸过程进行电阻抗图像重建,成像结果直观反映了人体肺呼吸过程的电阻抗变化。本论文的创新点主要体现在实现了同步测量的新型电阻抗断层成像系统,克服了异步测量相位差引起的测量误差,获得比较满意的成像结果。
[Abstract]:Electrical Impedance Tomography (Electrical Impedance) is a new functional imaging technology, which comes into being as a new functional imaging technology. Compared with traditional CT imaging technology, Electrical Impedance Tomography technology has non-invasive, no damage detection, functional imaging, simple structure, easy to use, fast imaging speed, can be measured multiple times, repeated use. Convenient for long-term continuous monitoring and other advantages. The traditional electrical impedance imaging system is designed and implemented according to the working mode of adjacent excitation and adjacent measurement proposed by the University of Sheffield in England. However, the adjacent measurement mode has the defect of phase difference between the measured data under the same excitation. The focus of this study is to design an electrical impedance imaging system for synchronous measurement. The paper mainly focuses on the following three aspects. First, the design of asynchronous measurement EIT system based on PXI FPGA: 1. Based on the original FPGA electrical impedance imaging system in the laboratory, the data acquisition part is improved to a data acquisition card based on PXI bus. The hardware platform of asynchronous measurement EIT system based on PXI FPGA is built, which is composed of tested object, data acquisition system and imaging computer, and debugging. 2. The software program. 3. 3 of the above system is developed by LabVIEW and MATLAB. The static imaging experiments of different size targets are carried out on the water tank of physical experiment, and the image reconstruction is realized by using the graphic reconstruction algorithm. Second, the design of synchronous measurement EIT system based on PXI bus: 1. 1. The hardware platform of synchronous measurement EIT system based on PXI bus is built, which is composed of tested object, excitation source module, switch module, data acquisition module, controller module and upper computer. Using LabVIEW and LabVIEW FPGA software platform, the synchronous measurement EIT system software. 3. 3 has been developed and perfected. Test the system performance. Experimental results show that the performance of the system meets the imaging requirements. 4. 4. The static and dynamic experiments of different target objects are carried out, and the image reconstruction algorithm is used to reconstruct the image. The imaging results of asynchronous measurement and synchronous measurement are compared. Third, the lung respiratory process image reconstruction of EIT system based on PXI bus. The most important thing to apply EIT system to the imaging of human breathing process is to modify the electrode. The paper contrasts and selects silver / silver chloride electrocardiogram electrode which is commonly used in the market. The impedance characteristic of the selected electrode is tested by impedance analyzer. The test results show that the characteristics meet the requirements of impedance measurement. 2. The electrical impedance image of human lung respiration process is reconstructed, and the imaging results reflect the electrical impedance changes of human lung respiration process. The innovation of this paper is mainly reflected in the realization of a new electrical impedance tomography system for synchronous measurement, which overcomes the measurement error caused by asynchronous measurement of phase difference and obtains satisfactory imaging results.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP391.41
本文编号：2169460
[Abstract]:Electrical Impedance Tomography (Electrical Impedance) is a new functional imaging technology, which comes into being as a new functional imaging technology. Compared with traditional CT imaging technology, Electrical Impedance Tomography technology has non-invasive, no damage detection, functional imaging, simple structure, easy to use, fast imaging speed, can be measured multiple times, repeated use. Convenient for long-term continuous monitoring and other advantages. The traditional electrical impedance imaging system is designed and implemented according to the working mode of adjacent excitation and adjacent measurement proposed by the University of Sheffield in England. However, the adjacent measurement mode has the defect of phase difference between the measured data under the same excitation. The focus of this study is to design an electrical impedance imaging system for synchronous measurement. The paper mainly focuses on the following three aspects. First, the design of asynchronous measurement EIT system based on PXI FPGA: 1. Based on the original FPGA electrical impedance imaging system in the laboratory, the data acquisition part is improved to a data acquisition card based on PXI bus. The hardware platform of asynchronous measurement EIT system based on PXI FPGA is built, which is composed of tested object, data acquisition system and imaging computer, and debugging. 2. The software program. 3. 3 of the above system is developed by LabVIEW and MATLAB. The static imaging experiments of different size targets are carried out on the water tank of physical experiment, and the image reconstruction is realized by using the graphic reconstruction algorithm. Second, the design of synchronous measurement EIT system based on PXI bus: 1. 1. The hardware platform of synchronous measurement EIT system based on PXI bus is built, which is composed of tested object, excitation source module, switch module, data acquisition module, controller module and upper computer. Using LabVIEW and LabVIEW FPGA software platform, the synchronous measurement EIT system software. 3. 3 has been developed and perfected. Test the system performance. Experimental results show that the performance of the system meets the imaging requirements. 4. 4. The static and dynamic experiments of different target objects are carried out, and the image reconstruction algorithm is used to reconstruct the image. The imaging results of asynchronous measurement and synchronous measurement are compared. Third, the lung respiratory process image reconstruction of EIT system based on PXI bus. The most important thing to apply EIT system to the imaging of human breathing process is to modify the electrode. The paper contrasts and selects silver / silver chloride electrocardiogram electrode which is commonly used in the market. The impedance characteristic of the selected electrode is tested by impedance analyzer. The test results show that the characteristics meet the requirements of impedance measurement. 2. The electrical impedance image of human lung respiration process is reconstructed, and the imaging results reflect the electrical impedance changes of human lung respiration process. The innovation of this paper is mainly reflected in the realization of a new electrical impedance tomography system for synchronous measurement, which overcomes the measurement error caused by asynchronous measurement of phase difference and obtains satisfactory imaging results.
【学位授予单位】：天津科技大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TP391.41
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