Electrical Impedance Tomography-Based Spatial Reconstruction of Admittivity in a Cylindrical Object

The paper discusses experimental measurement, simulation, validation, and reconstruction of complex admittivity, with all of the steps performed by utilizing electrical impedance tomography. After a brief introduction, the main aspects of the research are characterized, including the principle of the forward problem, in which the complete electrode model is embedded; the basics of the inverse problem, comprising an objective function solved with the Gauss-Newton method; and the impact of the objective function's regularization. The 8-electrode measuring configuration and the simulation environment are described in detail, as they facilitate the reconstruction process. The experiment-related portion of the paper outlines the measured voltages and phases for the homogeneous and inhomogeneous admittivity distribution inside the tomograph. Based on the measurement results, we reconstructed the image of the real and imaginary parts of the admittivity, using the EIDORS library to support the procedure. The obtained components were evaluated and compared with the actual position of the inserted object. The final images show that the determinability of the inhomogeneity position has generally improved through exploiting the real part of the complex admittivity; simultaneously, however, the stability of the imaginary part has visibly decreased.