嵌入式电阻抗系统研究

发布时间：2018-11-07 09:01

【摘要】：电阻抗断层成像技术(electrical impedance tomography,EIT)是近些年发展起来的新一代功能成像技术,利用阻抗测量系统对生物组织进行阻抗测量,通过分析相应的阻抗数据就能够取得丰富的与被测对象生理、病理状态相关的功能信息。EIT技术以其非侵入、安全无辐射、成本低廉、成像速度快、可连续测量且实时可视化等优点在医学成像技术领域备受关注。本文构建了以mini2440开发板为控制核心,以Qt开发的应用软件为平台,八个AD5933为电极的嵌入式电阻抗测量系统。通过运行于嵌入式操作系统上的阻抗测量软件,可设置AD5933芯片的工作模式,并控制数据采集的过程。控制及采集等指令通过I2C协议传输给嵌入式处理器。本论文完成了嵌入式八电极电阻抗系统研制,采集到的实部虚部信息以txt文件的形式存储在开发板中,并由开发的Qt阻抗测量软件对进行系统标定、数据处理、曲线绘制等。本系统构建成功后,进行了盐水槽实验,利用开发的Qt阻抗测量软件对试验数据进行分析处理并绘制曲线,在采集大量数据的基础上对系统进行性能测试,系统性能满足阻抗测量的精度及成像要求。最后,对盐水槽中不同位置的有机玻璃棒进行成像实验,采用高斯牛顿算法对数据进行归一化处理并成像。图像结果显示,该系统能很好地再现被测场域中物体的分布。实验结果表明该嵌入式阻抗测量系统具有体积小、集成度高、准确性好、功耗低、成本低、便携式等优点。
[Abstract]:Electrical Impedance Tomography (electrical impedance tomography,EIT) is a new generation of functional imaging technology developed in recent years. The impedance measurement system is used to measure the impedance of biological tissue. By analyzing the corresponding impedance data, we can obtain abundant functional information related to the physiological and pathological state of the object under test. EIT technology has the advantages of non-invasive, safe and radiation-free, low cost and fast imaging speed. The advantages of continuous measurement and real-time visualization have attracted much attention in the field of medical imaging technology. In this paper, an embedded impedance measurement system with mini2440 development board as the control core, application software developed by Qt as the platform and eight AD5933 electrodes as the electrode is constructed. Through the impedance measurement software running on the embedded operating system, the working mode of AD5933 chip can be set and the process of data acquisition can be controlled. The control and acquisition instructions are transmitted to the embedded processor via I 2 C protocol. In this paper, the embedded eight-electrode impedance system is developed. The real part virtual part information is stored in the development board in the form of txt file, and the system calibration, data processing, curve drawing and so on are carried out by the developed Qt impedance measurement software. After the successful construction of the system, the salt flume experiment was carried out, and the test data were analyzed and processed by the developed Qt impedance measurement software, and the curves were drawn, and the performance of the system was tested on the basis of collecting a large number of data. The system performance meets the precision and imaging requirements of impedance measurement. Finally, the experiments were carried out on the organic glass rods at different positions in the brine tank. Gao Si Newton algorithm was used to normalize and image the data. The image results show that the system can reproduce the distribution of objects in the field well. Experimental results show that the embedded impedance measurement system has the advantages of small volume, high integration, good accuracy, low power consumption, low cost and portable.
【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】：TP274.2;TP311.52;TP316

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