Study On Image Reconstruction Technology Of Real 3D ECT

Electrical capacitance tomography (ECT) based on capacitance sensing array in a kind of process tomography (PT). It has the advantages of being non-intrusive, fast in response, simple in structure and low in cost and so on. It is a great developing potential in measurement tomography.The objective of ECT is the 2D/3D visualization detection for content campaign state inside the closed pipeline containers and process equipment. Presently, the research mostly limited to 2D reconstruction. But in most cases, we need to get the 3D informations which cannot be directly obtained from 2D image. So the idea of 3D ECT image reconstruction has been put forward.Presently, there are two kinds of ideas of the study on the 3D ECT. The first one is called 2.5D ECT, it process the 2D images by interpolation in the third dimension after measuring the capacitors between the same-layer plate, and then reconstruct the 3D images. The second one is called real 3D ECT, it needn't process the 2D images, but reconstruct the real 3D image by measuring the capacitors between the single-layer and different layers of plates. Due to the lower axial resolution of 2.5D ECT, so the reconstruction image by it is much rougher than real 3D ECT. In our country, it has no research on real 3D ECT.In this paper, the main jobs are as follows:(1) Perfect the software packages of ECT. The author mainly wrote some programs which are applicable to the simulation analysis of the real 3D ECT, and then perfected the original finite element simulation software packages of the 2D/3D ECT.(2) Analyse the influence of structural parameters on the sensor system. The author mainly analyse the sensor plate axial clearance and plate rotation, gain a better sensor structure through the analysis of the capacitance, axial or radial sensitivity map and image reconstruction results by LBP method.(3) Write the the image reconstruction algorithm programs of the real 3D ECT system. The author writes a linear back-projection (LBP) method and Landweber iterative method. And then, reference to the evaluation parameters of 2D image reconstruction, confirmed the evaluation parameters of real 3D image reconstruction.