Exponential model normalization for electrical capacitance tomography with external electrodes under gap permittivity conditions

Abstract

A nonlinear normalization model which is called exponential model for electrical capacitance tomography (ECT) with external electrodes under gap permittivity conditions has been developed. The exponential model normalization is proposed based on the inherently nonlinear relationship characteristic between the mixture permittivity and the measured capacitance due to the gap permittivity of inner wall. The parameters of exponential equation are derived by using an exponential fitting curve based on the simulation and a scaling function is added to adjust the experiment system condition. The exponential model normalization was applied to two dimensional low and high contrast dielectric distribution phantoms by using simulation and experimental studies. The proposed normalization model has been compared with other normalization models i.e. Parallel, Series, Maxwell and Böttcher models. Based on the comparison of image reconstruction results, the exponential model is reliable to predict the nonlinear normalization of measured capacitance in term of low and high contrast dielectric distribution.

Measurement of Moisture Distribution in a Biomass Silo Through Electrical Capacitance Tomography

“…It can be seen that the effective permittivity increases with moisture content. These results are consistent with the conclusions from the theoretical values in [32][33][34]. As a result of the experimental tests, the effective permittivity of wood pellets is obtained with moisture content from 7.7% to 16.4%.…”

“…The effective permittivity of a mixture is determined by the permittivity of the individual components and their volume fractions. In order to obtain the effective permittivity of wood pellets with different moisture content, the exponential model [32] and the logarithmic model [33] are used to calculate the theoretical effective permittivity. For a mixture, these two models are widely used, and the calculated permittivity is closer to the actual value [34].…”

Simulation Studies on Image Reconstruction Algorithm for Portable Electrical Capacitance Tomography

“…is a potential difference measurement in a specific frequency, f and amplitude, V is injected [15,16]. Lastly, the capacitance value can be measured as follows:…”