Reconstruction of admittivity distribution without phase measurements in multi-frequency electrical impedance tomography (MFEIT)

Abstract Electrical impedance tomography (EIT) is an imaging modality based on applying electrical currents to the target object. Traditionally, both the magnitude and phase of electric potential measured on the target surface are required to reconstruct the admittivity, i.e. conductivity and permittivity, inside the target. However, measuring the phase of potential requires a more advanced EIT system than that used in amplitude data-based electrical resistance tomography. In this article, we propose a novel EIT method, amplitude-based multi-frequency EIT (AMFEIT), which reconstructs admittivity using only amplitude data. Therefore, AMFEIT can be used with devices that do not provide the phase data. The performance of AMFEIT is compared to that of traditional single frequency EIT using numerical and experimental tests. In simulations, the effects of certain modelling errors and choice of frequencies on the reconstruction quality are studied. In the experimental setup, several targets inside a water tank are imaged. Both the numerical and experimental tests support the feasibility of AMFEIT for reconstructing admittivity distributions. When the frequencies are properly chosen, the AMFEIT yields reconstructions that are of the same quality as those based on conventional EIT that uses phase data.