Research And Design Of Key Technology For Capacitance Tomography System

Electrical Capacitance Tomography(ECT)is a fast-growing process tomography(PT),which is a measure of the distribution of substances with different dielectric constants by means of measuring capacitance.ECT has the advantages of low cost,fast response,non-intrusive,good security and soon.Therefore,after several decades of development,the research results of ECT are approaching the perfect.Due to the "soft field" effect,the pathological characteristics and the difficulty of data collection of ECT,the development of ECT is limited.For the reasons mentioned above,this paper takes the ECT as the research object.On the basis of the theory of ECT,some technical problems in the study of ECT are studied and analyzed.Such as: the speed and precision of the image reconstruction algorithm can not be improved at the same time;Such as: image reconstruction algorithm speed and accuracy can not be raised at the same time;small capacitance measurement of the dynamic range,stray capacitance on the capacitance of the measured value of the impact;the impact of the design of the ECT sensor on the acquisition of data.In this paper,the above three major issues were discussed,simulation and optimization design,the specific content is as follows:1.This part gives a brief overview of the existing problems in image reconstruction algorithms and image reconstruction algorithms for ECT,then analyzes and compares the advantages and disadvantages of the current image reconstruction algorithms,and puts forward the further research direction of the image reconstruction algorithm.2.For the small capacitance measurement problems,the paper uses of a small capacitance measurement circuit based on AC excitation,and puts the circuit in a modular process.We use Pspice software's parameter scanning,amplitude frequency analysis and other functions to design the circuit simulation.The simulation results are used to analyze the circuit performance and to guide the design of circuit parameters.3.For the data source part of the component of ECT--the capacitive sensor,we analyze some impact on the capacitive sensor set data mining factors.According to the influence of these factors,we conduct orthogonal optimization experiments on ECT sensor,then give the optimization parameters of sensor plate angle,pipe inner diameter and outside diameter.