A Fast Electrical Impedance Tomography System with Parallel Multi-Carrier Excitation

M. Geversa, P. Gebhardta, B. Biesenbacha, M. Vogtb, T. Muscha

aRuhr-University Bochum, Institute of Electronic Circuits, 44780 Bochum, Germany

bRuhr-University Bochum, High Frequency Engineering Research Group, 44780 Bochum, Germany

Abstract

Electrical Impedance Tomography (EIT) is a well suited measurement method to determine the spatial conductivity distribution of multi-phase flows. In common systems a measurement environment is stimulated by a defined current pattern in a serial time-multiplexing manner. In order to increase the measurement rate, an EIT system with parallel multi-carrier excitation has been designed and implemented, which allows for data acquisition with up to 976 complete measurement cycles per second with 1024 samples per receive channel. In this work the implemented frequency-multiplexing concept will be compared to the more common time-multiplexing measurement approach. Furthermore a correction procedure for fluids with strongly frequency-dependent electrical properties will be presented.

Keywords: Electrical Impedance Tomography (EIT); Electrical Resistance Tomography (ERT); Frequency- Multiplexing (FDM); floating current source image processing;