An Optimized Measurement Strategy for 3D Electrical Capacitance Tomography.

In our previous work, a 24-electrode sensor with four planes is designed for 3D imaging in electrical capacitance tomography (ECT). When 3D ECT is applied to monitor dynamic processes, it is difficult to measure high-speed dynamic processes with full sampling. Besides, the cross-plane measurements are much smaller than the inter-plane measurements. While the measurements between adjacent electrodes are much larger than other measurements, which leads to a large dynamic range and high requirements for the accuracy of hardware. Therefore, a strategy for reducing the measurement number without too much degradation of image quality is studied. In this work, eight sets of measurements are compared in terms of sensitivity distribution, condition number, and dynamic range. A strategy for 3D ECT measurement is proposed. The measurements from widely separated electrodes and adjacent electrodes can be ignored in image reconstruction. Simulation and experiments are carried out. Results show that shapes and distributions of objects can be reconstructed using the proposed strategy without heavy distortion and artifacts. Besides, the measurements are reduced by 21%. In comparison, correlation coefficients of the reconstructed images are reduced by 2% in the noise-free case and even increase for several distributions in the noisy case, which indicates the effectiveness of the proposed strategy.