Modelling an electrical capacitance tomography sensor with internal plate electrode

Electrical capacitance tomography (ECT) is one of process tomography technique which developed rapidly in recent years. Classical electrical capacitance tomography is an imaging technique to obtain the permittivity distribution inside a closed pipe by using the electrodes mounted outside. However, it suffers from the poor sensitivity in the center. In the present paper, a new type of sensor with an internal plate electrode arrangement positioned in the pipe´s center is proposed. An external-electrode sensor and a sensor with an annular internal electrode are also investigated. In order to compare the three different types of sensors, sensitivity maps are generated and the Landweber iterative algorithm is used for image reconstruction. The simulation experiments are carried out to evaluate the new type of sensor. The results show that, due to the internal electrode, it can improve the sensitivity in the central sensing area and thus is able to produce improved images. By using the new proposed sensor, it has a larger sensing area and can achieve similar image quality when compared to use the internal annular sensor.