A Joint Image Reconstruction Method for Capacitively Coupled Electrical Impedance Tomography

Capacitively coupled electrical impedance tomography (CCEIT) is a contactless improvement of electrical resistance tomography (ERT) that uses both the real and imaginary parts of the impedance. To make better use of the two parts, a novel joint image reconstruction method with structural grouping guidance for CCEIT is proposed in this work. The method presents a fusion-while-reconstruction approach to implement data fusion of the real part information and imaginary part information during image reconstruction. A joint reconstruction model is developed from two aspects, including the joint reconstruction of the impedance and the structural grouping guidance. The first aspect implements the simultaneous utilization of the two parts during image reconstruction and considers their different contributions to the reconstruction. The second aspect introduces the grouping information of the gas-liquid two-phase flow and designs a structural grouping term by group least absolute shrinkage and selection operator (LASSO). With the developed model, the proximal gradient descent (PGD) algorithm is employed to realize the joint image reconstruction and obtain the reconstructed image. Experiments were carried out with a 12-electrode CCEIT system. The results verified the effectiveness of the proposed joint image reconstruction method. Compared with the conventional method which adopts the fusion-after-reconstruction approach by image fusion, the proposed method has better imaging performance and higher reconstruction efficiency. In addition, the structural grouping guidance is effective in reducing the image artifacts and further improving the image quality.