一种48电极可配置电容层析成像系统模型
A Model of Electrical Capacitance Tomography System with Configurable 48 Electrodes

针对已有电容层析成像(ECT)技术的独立电容较少、反问题方程数过少及其解不唯一的问题,提出了一种48电极的ECT系统模型及模型组合电极策略。首先,通过组合电极策略将多个临近电极组合成一个电极,使原48电极ECT系统配置为8、12、16或24电极ECT系统,从而获得绕管道轴心旋转不同角度的多个具有相同电极数ECT系统;然后,通过有限元仿真和图像重构算法成像。该模型可使ECT反问题的方程组中电容数成倍增加,从而改善了ECT反问题方程组因方程数过少而引起的解不唯一的不适定问题,解决了增加电极数而电极片面积却减小引起的电容值减小问题。仿真结果表明:所提出的ECT模型及其组合电极策略可重构图像,并能通过增加测量电容数提高重构图像质量;在系统加入10％标准差白噪声时,图像错误率下降约6％。
A model of electrical capacitance tomography (ECT) system with configurable 48 electrodes and a strategy to combine electrodes are proposed to increase the capacitances of the current ECT system and to solve the equations of the ECT inverse problem. The strategy combines some adjacent electrodes as one electrode so that the ECT system with 48 electrodes is reconfigured as a ECT system with less electrodes, such as 8 electrodes,12 electrodes, 16 electrodes or 24 electrodes. Several ECT systems with the same number of electrodes and the different rotation angles around the pipeline are obtained. Then the finite？？element modeling and an image reconstruction algorithm are adopted for imaging. The model increases the number of capacitances in the equations of the ECT inverse problem, thus the ill？？posedness of the equations of the ECT inverse problem caused by less equations is improved. The model also solves the problem that the capacitance value will decrease when the number of electrodes increases. Simulation results show that the proposed model and strategy can reconstruct images and improve the fidelity of reconstructed images by increasing the number of capacitances, and the error rate of images decreases by about 6% when a white noise with a standard deviation of 10% is added into the system