Study On3D ECT Sensor Structure Parameters Based On Comsol

Electrical Capacitance Tomography(ECT) technology, is a kind of methods that placingamount of electrodes around the object to be measured. Each set of two electrodes constitutesa pair of electrodes to measure the capacitance value between them. Using these measuredcapacitance values, it can reproduce the distribution of different dielectric constant materialinside the object to be measured by the image reconstruction algorithms. Compared with otherdetection techniques, electrical capacitance tomography has many advantages, such as itssimple structure, non-invasive, inexpensive, portable, no radiation and pollution, easy toimplement, fast response time etc. It has been used in the petroleum, chemical, power andmetallurgical industries, especially for two-phase flow measurements with a wide range ofapplications.Electrical Capacitance Tomography technology is mostly limited to the study oftwo-dimensional ECT technology now, which uses a single plate of electrodes outside themeasured object to get a profile of image information. Three dimensional ECT technology is anew direction in recent years. In terms of the sensors, compared with two-dimensional ECTtechnology, it uses a multiple layer structure of electrodes. Surrounding the object, a multipleof electrodes are placed to obtain the information of sensitive field. Through the information, itallows to build the three dimensional reconstruction inside the object, and its rebuilding effecthas been more comprehensive and intuitive.In this paper, firstly multiple physics software Comsol Multiphysics is used to build thethree-dimensional models of ECT system, then the reconstruction of ECT system can beobtained by the Matrix Laboratory(Matlab) software. In the study of image reconstructionalgorithm, this paper uses the LBP algorithm with automatic filtering threshold in order toaccelerate the elimination of gray artifacts and get better quality of ECT reconstructed image.The algorithm is called automatic adaptive threshold filtering method.This paper also studies the impact of the performance of sensor in the changes of thesensor structure. The sensor with24electrodes are studied here. Stay other performanceindicators of the sensor the same, change the arrangement of the electrodes, three kinds ofsensors with different electrodes arrangements are designed here. By calculating the maximum and minimum capacitance value, the capacitance dynamic range, sensitivity homogeneity, thecondition number of the sensitivity matrix, image reconstruction and other aspects, this paperstudies the effect of sensor performance on the changes of sensor structure of the ECT system.This paper introduces the Industrial Tomography Systems(ITS) and analyzes theadvantages of its sensors. Because it is only capable of three-dimensional data acquisition forECT, but lack of direct three-dimensional reconstruction algorithm, so it can not get a directthree-dimensional image reconstruction. This reflects the importance and the developmentspace of the direct three-dimensional ECT reconstruction algorithm. It also can verify thecorrectness of the simulation model through comparing its each parameters with the systemitself.