Evaluation of Electrical Capacitance Tomography Sensor with Composite Electrodes

M. Wu 1,2, J. M. Ye 1, H. Q. Che 1,2 and H. G. Wang 1

1 Institute of Engineering Thermophysics -- Chinese Academy of Sciences, Beijing 100190,

2 University of Chinese Academy of Sciences, Beijing 100049, China yejiamin@iet.cn

ABSTRACT

As a soft-field tomography technique, the sensitivity of a circular or concentric electrical capacitance tomography (ECT) sensor decreases with the increase in the distance from the electrodes. To improve the sensitivity distribution and enhance the image quality, a new ECT sensor with composite electrodes (CE), i.e. the external electrodes, internal electrodes and middle electrodes, is proposed in this paper. The ECT sensors with internal-external electrodes (IEE) and ECT sensors with external electrodes (EE) are -designed for comparison. The number of external, internal and middle electrodes is 12, 4 and 4, respectively. A permittivity distribution with four bars is used as the true distribution. Linear back projection (LBP) algorithm is used for image reconstruction. The quality of reconstructed images is evaluated in terms of correlation coefficient compared with the true distribution. Simulation results show that the CE sensor can provide the best image quality.

Keywords Electrical capacitance tomography, sensor design, numerical simulation