Name: Lasse Heikkinen

Email: lasse.heikkinen@uku.fi

CompanyName: University of Kuopio

Country: Finland

Abstract: Simultaneous reconstruction of electrode contact impedances and internal electrical properties


In some EIT applications the voltage drops due to the contact impedance between electrodes, and the domain to be imaged is essential.
Especially, in applications in which
the current carrying electrodes are used in voltage measurements. One such industrial application is gas holdup estimation in a mixing tank. In such a case the electrodes and electrode contact impedances have to be modelled. In this study the reconstruction of the electrode contact impedances
simultaneously with internal electrical properties is studied. The complete electrode model is used as a forward model in which
effect of the electrodes and the electrode contact impedances are included. The inverse problem is a non-linear estimation problem which is solved by the Gauss-Newton algorithm.
The proposed method is tested with real measurement data. Two series of measurements were performed. In both cases liquid was assumed to be purely resistive and the contact impedances were assumed to be real valued.
In the first one the conductivity of the liquid was assumed to be homogeneous and electrode contact impedances were assumed to be equal on all the electrodes. In this case
the performance of the proposed method is studied. In the second one the electrode contact impedances were assumed to be different
on all the electrodes. The measurements were carried out in a 3D cylinderical tank.
The number of the electrodes was 16. In the measurements a reference measurement protocol was used. The results shows that the proposed method works well with real measurements

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