Research On Data Scanning Method And Control System Of Sector Magnetic Induction Tomography

Magnetic induction tomography detection technology is a non-contact detection method,which uses the principle of eddy current detection and produces high-frequency electromagnetic field on the measured object through the coil,so that the magnetic field where the object is located produces the eddy current,and then uses the induction coil to detect,and the electrical impedance distribution image of the measured object is established by image reconstruction method.Compared with CT,MRI and other imaging methods,magnetic induction tomography detection technology has real-time,non-invasive,non-contact,low cost of detection and so on,therefore,as a mature non-destructive testing technology,magnetic induction detection technology has important research value and significance.In this thesis,the basic principle of magnetic induction tomography detection technology is studied,and a set of fan-shaped rotating scanning magnetic induction tomography detection system is designed.The system combines the fan-shaped rotation method and the magnetic induction tomography detection method.In the fan-shaped rotation scanning control part,Arduino is used as the core controller of the control system,and uses the stepping motor displacement table to achieve the measured object rotating,and then designs the host computer software interface of the control system.In the magnetic induction tomography detection part,a band pass filter is designed with OPA603 as the main device to filter the high frequency noise.In this thesis based on the AD8130 amplifier to filter and amplify the collected detection signal,and based on the phase detection circuit of AD8302 phase detector chip to transfer information to the PC side by the A/D converter sampling processing,as well as provides effective data for image reconstruction.In this thesis,In the single channel detection mode,the two modes of static and 180° fan rotation were used to detect and the experiment time of the two groups was set 30 min.In the multi-channel detection mode,static and 180° fan-shaped rotation 5-channel detection mode were used to verify the experiment and the experiment time of the two groups was set 50 min.The experimental results show that the system in the situation of air field,the system can eliminate the drift of the system after 35 min later.And in the situation of existing measured objects,the phase difference detected by each detection channel is significantly different from the data detected in the air field condition.And then in the single channel detection mode and fan scan method,each acquisition cycle is 3min,every 10 s rotation 10°.The results show that the amount of data detected by the detection system of in which the fan-shaped rotation scanning method is loaded is 18 times of the amount of data detected by the static acquisition method in the same detection time.Thus,under the 5-channel detection mode,the system of the fan rotation scanning method is loaded,and the amount of data collected can be increased by 18 times in the same detection period.