Three- dimensional Effects in Electrical Impedance Tomography

M. Wang

Department of Electrical Engineering and Electronics* UMIST. P.O. Box 88, Manchester M60 1QD, UK

M. Wang is the member of the Virtual Centre for Industrial Process Tomography

Abstract - An investigation of 3-dimesional (3D) effects on electrical impedance tomography is reported. 3D effects in measurement, simulation and analytical models are described. A 3D attenuation range (75% attenuation) from the sensing plane is suggested as one third of process vessel?s diameter. The imaging trajectory of an axially moving object is found towards the central axis of a process vessel when a 16- electrode sensing ring is employed. The paper also reports the use of a guarded electrode scheme can reduce the imaging displacement but has no evident effects at the compressing the sensing space.

Keywords : 3D sensing space, Attenuation ratio, 3D-convergence effect, Single-plane sensor, Guarded electrode scheme.