A review on image reconstruction algorithms for electrical capacitance/resistance tomography

Abstract

Purpose Electrical capacitance tomography (ECT) and electrical resistance tomography (ERT) are promising techniques for multiphase flow measurement due to their high speed, low cost, non-invasive and visualization features. There are two major difficulties in image reconstruction for ECT and ERT: the “soft-field”effect, and the ill-posedness of the inverse problem, which includes two problems: under-determined problem and the solution is not stable, i.e. is very sensitive to measurement errors and noise. This paper aims to summarize and evaluate various reconstruction algorithms which have been studied and developed in the word for many years and to provide reference for further research and application. Design/methodology/approach In the past 10 years, various image reconstruction algorithms have been developed to deal with these problems, including in the field of industrial multi-phase flow measurement and biological medical diagnosis. Findings This paper reviews existing image reconstruction algorithms and the new algorithms proposed by the authors for electrical capacitance tomography and electrical resistance tomography in multi-phase flow measurement and biological medical diagnosis. Originality/value The authors systematically summarize and evaluate various reconstruction algorithms which have been studied and developed in the word for many years and to provide valuable reference for practical applications.

Size Projection Algorithm: Optimal Thresholding Value Selection for Image Segmentation of Electrical Impedance Tomography

“…In EIT technique, according to the measured boundary data (i.e., measured boundary voltages), we want to obtain the actual distribution of materials (i.e., actual object distribution) which is often unknown in practice. Commonly, various tomographic algorithms [20] are employed to reconstruct a grey-value image (i.e., computed object distribution) which is often a 2D grey-level or colour palette-based image. e 2D image was demonstrated and widely used as an approximate representation of the cross-sectional configuration of the actual material distribution even if it is not exactly the same.…”

Investigation of gas–solid bubbling fluidized beds using ECT with a modified Tikhonov regularization technique

“…Because Eq. is too complicated, a simplified linear equation in a normalized form is always used: where g is the normalized permittivity and λ is the normalized capacitance defined as where C M is the measured capacitance for an arbitrary permittivity distribution and C H and C L are the capacitances when the sensor is full of high‐ and low‐permittivity materials, respectively.…”

“…Second, due to the ill‐posed and ill‐conditioned property of the reconstruction process, the reconstructed results are sensitive to raw capacitance measurement noise. To address these problems, different reconstruction techniques, including single‐step and iterative algorithms, have been proposed and have been reviewed by Yang and Peng and Cui et al Among all the proposed algorithms, linear back projection (LBP), Tikhonov regularization, and Landweber iteration are three most popular methods, in which the former two are single‐step while the latter is iterative.…”

Real-Time Imaging and Holdup Measurement of Carbon Dioxide Under CCS Conditions Using Electrical Capacitance Tomography

“…ECT is one of the most promising techniques for multi-phase flow measurement, which has been successfully applied to gas-oil two-phase flows in oil industry [16] and gas-liquid-solid three-phase flows [17]. It has several advantages such as low cost, high speed and non-invasive compared with other tomographic techniques [15], [18], [19].…”