Comparison of electrical capacitance tomography sensors with internal-external electrodes

In this paper, an ECT sensor with 12 external electrodes and 4 internal electrodes (IEE) is designed to investigate the quality of reconstructed images in circular and annular areas. The sensitivity distribution and the capacitance between different electrode pairs are calculated using a finite element method (FEM), and then used to reconstruct images using Landweber iteration algorithm. For the circular area, three different measuring strategies are considered, and then compared with a traditional ECT sensor (EE). For the annular area, three different measuring strategies, the internal electrode with/without screen, the EE sensor are considered and compared. The results show that, the IEE sensor can improve the image quality in circular areas, and only in certain circumstances, the IEE sensor can improve the image quality in annular areas comparing with the EE sensor.