Research On Electrical Impedance System

EIT(Electrical Impedance Tomography)is a kind of new imaging technology developed in recent years,which technique can measure impedance data of tissues using the impedance measurement system,Abundant physiological and pathological information can be acquired by analyzing the corresponding impedance data.EIT technology has become an ideal stage noninvasive imaging technique in the medical field with its non-invasive,non-radiation,safety,low cost,fast imaging,continuous measurement and real-time visualization,etc.This paper constructs an electrical impedance measurement system,which is composed of mini2440 development board as core controller,the user-interface software based on Qt platform and 8 AD5933 chips as electrodes.We can set the working mode of AD5933 and control the process of data collection by running impedance measurement software of embedded OS,which transfer information through I2C communication protocol.This paper complete the research of 8-electrodes electrical impedance measurement system,whose data of real or imaginary with text file is stored in development board,achieving system calibration,data processing and curve plotting through Qt impedance measurement software,etc.After the system was constructed successfully,then we draw a curve by the Qt impedance measurement software,on the basis of collecting a large amount of data,to test the system performance.Performance of the system satisfies the demands of impedance measurement precision and imaging.Finally,we take organic glass rod imaging experiment in salt water tanks in the different position,to normalize processing and imaging with Gauss-Newton algorithm.Results of image indicate the system can reappear well the field distribution of the domain objects.All in all,the experiment result shows that electrical impedance measurement system has advantages of low-cost,portable,compact,dedicated sexual and other purposes.