The Design Of EIT Hardware System Based On Virtual Instrument

There are many sophisticated imaging way in the medical areas, such as X-ray、CT technology, but each method has its basic shortcomings.The development of two-phase flow or multiphase flow in the industrial areas is relatively slow. The reason is a lack of effective detection technology.So a safe and reliable technology was urgently needed to meet the requirements in the medical and industrial areas.Electrical Impedance Tomography(EIT) is a new topographic image technology which originated in western developed countries.EIT was researched from the twentieth century at the end of the seventies. It have lots of advantages, such as visualization、non—invasive、low—cost、real-time imaging and so on. So the researchers of measurement technique are interesting in it in the industry and Medical. Because of its potential value, it has become an important research direction. After of ten years, the virtual instruments which National Instruments advanced had a greater influence on the field of instrumentation. It change many methods of the traditional measurement and control. As technology advances and progress, virtual instrument technology give the test, measurement, and control and other areas to provide a very good design platform.This article introduced the virtual instrument into the electrical impedance imaging, so that electrical impedance tomography can be deeper and wider development.The author studied the hardware structure of the EIT, then designed the electrical impedance imaging with virtual instruments at the core. The author also designed the entire hardware system and its sub-modules with the idea of modular.The main complete tasks are as follows:(1) The performance of the EIT hardware system is analyzed. On the base of describing the way of driver and measurement, the author design EIT system and describe the hardware structure of it.(2) The author firstly introduced the virtual instrument into the electrical impedance imaging from the perspective of hardware and software. According to two characteristics, the author make the EIT hardware circuits with virtual instruments as the core.(3) The program which is compile by Verilog HDL runs on the CPLD.(4) On the base of describing and contrasting the method of signal demodulation, the author select the digital quadrature demodulator and program for it by the Lab VIEW.(5) the modules of the system are tested, and eventually we build the EIT hardware system. A series of experiments is do on the hardware system. The results of the experiments show the hardware system of EIT is feasibleFinally, the author made recommendations for the next work and the system preformance.