Abstract. Electric
Field Tomography (EFT) is a method of electromagnetic quasistatic tomography enabling
contactless obtaining of information about the spatial distribution of the
electrical properties of the object under study, probing it with a variable
electric field. The problem with the implementation of EFT is the extraction of
the useful signal (phase shift) related with Maxwell-Wagner relaxation in the
object under study from the total measured change in the phase of the signal.
The largest contribution to the measurement error in the unipolar EFT systems
proposed earlier is made by the variations in the electrical capacitance of the
measuring electrodes and the object under study relative to the common circuit
of the system. The objective of this work is to demonstrate the feasibility of
EFT system with differential excitation and field detection, which can
significantly reduce the effect of such errors and other interference on the
measurement results. The method of numerical simulation demonstrates the
localization of the sensitivity zone of differential measurements near the
equipotential line of the electric field. This makes it possible to use known
methods for solving the inverse problem of quasistatic tomography, in
particular, the method of convolution and back projection along the lines of
maximum sensitivity. It turned out that both phase and amplitude measurements
can be used to reconstruct images in the differential EFT.
Keywords:
quasistatic electromagnetic tomography, electric field, visualization, finite
differences in the time domain.
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