Low-power electrical impedance tomography spectroscopy

Abstract

Purpose This paper aims to present an approach based on electrical impedance tomography spectroscopy (EITS) for the determination of water and ice fraction in low-power applications such as autarkic wireless sensors, which require a low computational complexity reconstruction approach and a low number of electrodes. This paper also investigates how the electrode design can affect the reconstruction results in tomography. Design/methodology/approach EITS is performed by using a non-iterative method called optimal first order approximation. In addition to that, a planar electrode geometry is used instead of the traditional circular electrode geometry. Such a structure allows the system to identify materials placed on the region above the sensor, which do not need to be confined in a pipe. For the optimization, the mean squared error (MSE) between the reference images and the obtained reconstructed images was calculated. Findings The authors demonstrate that even with a low number of four electrodes and a low complexity reconstruction algorithm, a reasonable reconstruction of water and ice fractions is possible. Furthermore, it is shown that an optimal distribution of the sensor electrodes can help to reduce the MSE without any costs in terms of computational complexity or power consumption. Originality/value This paper shows through simulations that the reconstruction of ice and water mixtures is possible and that the electrode design is a topic of great importance, as they can significantly affect the reconstruction results.

A Review on Electrical Impedance Tomography Spectroscopy

“…Optimal Approximation is a non-iterative statistical method. This method has been used for EIT, but not yet used for EITS other than in simulations [23,53]. It is well described in [7] and used in [68] for robotic applications.…”

“…In the frequency difference method, the variation V a of an electrical property EP a of a material a is V a (EP a ) = EP a ( f i , t 0 ) − EP a ( f 0 , t 0 ) (23) where f 0 is the reference frequency and f i is the frequency value for index i at time t 0 . In this static imaging method, the difference between the value of the electrical property of interest in different frequencies is obtained for a.…”

“…EITS has also been a promising technology for other applications, such as for material accretion detection, as proposed in [23] for monitoring of ice and water mixtures. However, challenges such as temperature dependency of the electrical properties and how environmental conditions will affect the structure of the ice can present a challenge [24].…”

Electrical Impedance Tomography Signal Conditioning for Lung Imaging Applications

“…Moreover, these devices are heavy, and therefore are kept at stationary facilities, and require a high capital of maintenance cost as well as imaging cost. EIT provides an alternative solution for these disadvantages in lung function monitoring [20,21]. In surgery, the applications of EIT devices are very promising in case of many diseases for the detection and real-time imaging purposes of common and serious complications occurring during thoracic and pulmonary surgery [6,14,15,20].…”