Reconstruction of electrical capacitance tomography images based on fast linearized alternating direction method of multipliers for two-phase flow system

Electrical capacitance tomography (ECT) has been applied to two-phase flow measurement in recent years. Image reconstruction algorithms play an important role in the successful applications of ECT. To solve the ill-posed and nonlinear inverse problem of ECT image reconstruction, a new ECT image reconstruction method based on fast linearized alternating direction method of multipliers (FLADMM) is proposed in this paper. On the basis of theoretical analysis of compressed sensing (CS), the data acquisition of ECT is regarded as a linear measurement process of permittivity distribution signal of pipe section. A new measurement matrix is designed and L1 regularization method is used to convert ECT inverse problem to a convex relaxation problem which contains prior knowledge. A new fast alternating direction method of multipliers which contained linearized idea is employed to minimize the objective function. Simulation data and experimental results indicate that compared with other methods, the quality and speed of reconstructed images are markedly improved. Also, the dynamic experimental results indicate that the proposed algorithm can fulfill the real-time requirement of ECT systems in the application.

Graphical abstractIt is an ECT system flowchart for the gas–solid flow measurement in the lab-scale fluidized bed equipment. The fast linearized alternating direction method of multipliers (FLADMMs) is used as the image reconstruction algorithm of ECT system. The experimental results indicate that the quality and the speed of reconstructed images are markedly improved.Figure optionsDownload full-size imageDownload as PowerPoint slide