Modelling of capacitance tomography sensors

Current electrical capacitance tomography (ECT) systems reconstruct cross-sectional images directly using the 'raw' capacitance data measured from the multielectrode sensors. These 'raw' measurements are affected by the pipe wall and/or external interelectrode capacitances, and hence it is impossible to reconstruct accurate quantitative images. The author analyses four types of pipe-mounted sensor, as categorised by their electrode and radial screen arrangements, and gives methods of calculating the internal interelectrode capacitances which exclude other interfering capacitances, thus enabling quantitative measurements and improved images to be obtained.