Electrical Impedance Tomography Using the Extended Kalman Filter

Abstract

In this paper, we propose an algorithm that, using the extended Kalman filter, solves the inverse problem of estimating the conductivity/resistivity distribution in electrical impedance tomography (EIT). The algorithm estimates conductivity/resistivity in a wide range. The purpose of this investigation is to provide information for setting and controlling air volume and pressure delivered to patients under artificial ventilation. We show that, when the standard deviation of the measurement noise level raises up to 5% of the maximal measured voltage, the conductivity estimates converge to the expected vector within 7% accuracy of the maximal conductivity value, under numerical simulations, with spatial a priori information. A two-phase identification procedure is proposed. A cylindrical phantom with saline solution is used for experimental evaluation. An abrupt modification on the resistivity distribution of this solution is caused by the immersion of a glass object. Estimates of electrode contact impedances and images of the glass object are presented.

Direct Reconstruction of Pharmacokinetic-Rate Images of Optical Fluorophores From NIR Measurements

“…In our work, as proposed in [38] and [39], we regard the covariance matrices , , and as tuning parameters and choose the values that lead to the minimum norm (trace sum) of the error covariance matrix within biological limits. We empirically evaluate the convergence of EKF and the goodness of the compartmental model fit by studying the change in the residuals of measurements with respect to the number of iterations given the covariance matrices , , and [41]. For numerical results, see Sections VI-A and VI-B.…”

Boundary Estimation Techniques in Two-phase Flows using Electrical Impedance Tomography: A Review

“…In [25], using convection diffusion model, the velocity fields together with the conductivities is estimated using EKF. In regard to the clinical applications, EKF has been applied to imaging of resistivity changes inside the human thorax [26].…”

Determination of Cardiac Ejection Fraction by Electrical Impedance Tomography using a Hybrid Heuristic Approach, a Simulation Study

“…This technique has been largely applied in different fields, as industrial monitoring [1], geophysics [2], and biomedical engineering [3,4]. In the context of the latest field, recent work [5] has discussed viability of EIT to continuous monitoring of cardiac ejection fraction, and other related works [6][7][8] have shown preliminary results on the same subject.…”