Dual-modality four-wire electrical capacitance and resistance tomography

For some applications, it is necessary to visualize an industrial process by both electrical capacitance tomography (ECT) and electrical resistance tomography (ERT). For this purpose, dual-modality ECT/ERT has been developed. A major challenge in this task is the constant changing of electrical property, from predominantly conductive to mainly dielectric. The current ERT systems do not perform as well as ECT systems, limiting the integration of ECT and ERT to be a dual- modality system. In this work, the use of voltage-excitation for ERT and a 4-wire sensor structure allows effective fusion of ERT and ECT in a single set of electrodes to measure capacitance and conductance simultaneously in a spatially and temporally coherent way.