An Image Reconstruction Algorithm for a 12-Electrode Capacitively Coupled Electrical Resistance Tomography System Under 2-Electrode Excitation Strategy

An image reconstruction algorithm, which is developed for a 12-electrode capacitively coupled electrical resistance tomography (CCERT) system under 2-electrode excitation strategy, is proposed. Based on L-curve and Reginska’s method, truncated singular value decomposition (TSVD) is used to reconstruct the initial image. The algebraic reconstruction technique (ART) algorithm is used to obtain the final reconstructed image. Image reconstruction experiments are conducted by a 12-electrode CCERT system. The proposed algorithm (TSVD + ART) is compared with conventional linear back projection (LBP), Tikhonov, Landweber, ART, simultaneous iterative reconstruction technique (SIRT), total variation (TV), conjugate gradient (CG), and TSVD to evaluate its image reconstruction performance. Image reconstruction results show the proposed algorithm (TSVD + ART) can effectively exploit the advantages of 2-electrode excitation strategy and hence realize higher quality image reconstruction. Under 2-electrode excitation strategy, the proposed algorithm has an obvious advantage over conventional image reconstruction algorithms. Under 1-electrode excitation strategy, the image reconstruction performance is comparable or slightly improved compared with that of conventional image reconstruction algorithms. Image reconstruction results also indicate the TSVD is effective to obtain the initial reconstructed image. The quality of the initial reconstructed image can be significantly improved compared with that of classic LBP, either under 2-electrode excitation strategy or 1-electrode excitation strategy.

I. Introduction

Electrical resistance tomography (ERT) is a popular electrical tomography (ET) technique and is widely applied in many research fields [1]–[14]. Capacitively coupled electrical resistance tomography (CCERT) is a contactless ERT technique. Compared with the conventional ERT which uses contact measurement, the electrodes of CCERT are not in direct contact with the measured fluids. The negative effects of contact measurement (polarization and electrochemical corrosion) can be avoided. However, the relevant image reconstruction research for this relatively new technique is not sufficient [15]–[19].