Research On Optimization Of Sensor Structure Parameters Of Direct3D Electrical Capacitance Tomography

Electrical Capacitance Tomography (ECT) is a PT technique which combined withmedical CT and modern detection technique. This technique aims at visualization of thepermittivity distribution of a dielectric object based on the capacitances, different angles"projection" information, which are obtained from the sensor arrays laid on the measuredpipeline or vessel by a non-invasive way. Through the appropriate image reconstructionalgorithm, it seeks to reconstruct the distribution of medium (permittivity) in the measuredobject field using the measured capacitances. The ECT technique has the advantages ofnon-invasive measurement, non-contact, fast in response, low in cost, so it is widely usedin industrial process detection.The traditional ECT technique can reconstruct a2D image at some point and thenobtain the3D images by interpolating the2D images in the third dimension. However,most of the process occurs in a3D space. Direct3D ECT measures the capacitancesbetween not only the same layer but also the different layers of electrodes, so the3Dimages directly generate in the image reconstruction process, not through thetwo-dimensional tomography. In recent years, the direct3D ECT technique gets more andmore attention.In this paper, the following work is completed:(1) Learning the Comsol Multiphysics finite element analysis software. Regard theelectrostatic field in the AC/DC module as the physical field of simulation. Build the direct3D sensor model by geometric modeling, electrostatic field and material settings, meshingand other steps.(2) Build8direct3D ECT simulation models. Analyze the influence of structureparameters on the sensor from capacitances of the empty and full pipe, sensitive analysisand cond, image reconstruction quality by changing the structure parameters, and thendetermine the optimal structure. (3) Reconstruct3D images by a Landweber iteration method with non-zero threshold,and then the3D visualization of the reconstructed result is achieved by iso-surface andvoxels filled.