Ultrasound guided electrical impedance tomography for 2D free-interface reconstruction

Abstract

The free-interface detection problem is normally seen in industrial or biological processes. Electrical impedance tomography (EIT) is a non-invasive technique with advantages of high-speed and low cost, and is a promising solution for free-interface detection problems. However, due to the ill-posed and nonlinear characteristics, the spatial resolution of EIT is low. To deal with the issue, an ultrasound guided EIT is proposed to directly reconstruct the geometric configuration of the target free-interface. In the method, the position of the central point of the target interface is measured by a pair of ultrasound transducers mounted at the opposite side of the objective domain, and then the position measurement is used as the prior information for guiding the EIT-based free-interface reconstruction. During the process, a constrained least squares framework is used to fuse the information from different measurement modalities, and the Lagrange multiplier-based Levenberg–Marquardt method is adopted to provide the iterative solution of the constraint optimization problem. The numerical results show that the proposed ultrasound guided EIT method for the free-interface reconstruction is more accurate than the single modality method, especially when the number of valid electrodes is limited.

An augmented Lagrangian trust region method for inclusion boundary reconstruction using ultrasound/electrical dual-modality tomography

“…In this subsection, to verify the effectiveness of the proposed UEIT method, a set of comparative tests are carried out. The single-modality EIT shape reconstruction results are obtained by L-M algorithm [19]. In comparative tests, the heart-shape inclusion is used as the test target, and its boundary can be represented by Limacon function:…”

“…The narrowband level set method was used to reconstruct the 2D and 3D EIT images, and the prior ultrasound knowledge about the boundary of the target inclusion was used to speed up the level set algorithm to converge in less iterations. Liang et al [19] presented a shape-based method combining the ultrasound reflection and transmission data to improve the EIT free-interface reconstruction accuracy. To make full use of the measurements of EIT and URT, a shape-based ultrasound/electrical dual-modality tomography is presented to directly reconstruct the boundary of the inclusion in this paper, and the augmented Lagrangian trust region method is proposed to solve the dualmodality shape inverse problem.…”

A Triple-Modality Ultrasound Computed Tomography Based on Full-Waveform Data for Industrial Processes

“…Therefore, a multi-modality approach, that can facilitate multiple reconstruction methods, is expected to result in more accurate imaging, as it can process measurements coming from different signal's features. Several studies show that dual-modality UPT (transmission/reflection) is superior to single-modality, confirming that multi-modality offers tremendous benefits [16], [17]. As a result, a novel triplemodality image reconstruction method combining AA and TOF transmission as well as TOF reflection is proposed.…”

A Lagrange-Newton Method for EIT/UT Dual-Modality Image Reconstruction

“…However, the number of the ultrasonic transducer is usually not enough compared to the need for the imaging accuracy in practical applications. Fortunately, UT can obtain some accurate local media distribution information even the number of the ultrasonic transducer is limited [28,29]. Thus, the prior information about the media distribution from UT is promising to improve the imaging accuracy of EIT.…”