• Title, Summary, Keyword: Electrical resistance tomography

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Electrical Resistance Tomography: Mesh Grouping and Boundary Estimation Algorithms

  • Kim Sin;Cho Hyo-Sung;Lee Bong-Soo
    • International Journal of Contents
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    • v.1 no.1
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    • pp.1-5
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    • 2005
  • This paper presents the development and application of electrical resistance imaging techniques for the visualization of two-phase flow fields. Two algorithms, the so-called the mesh grouping and the boundary estimation, are described for potential applications of electrical resistance tomography (ERT) and results from extensive numerical simulations are also presented. In the electrical resistance imaging for two-phase flows, numerical meshes fairly belonging to each phase can be grouped to improve the reconstruction performance. In many cases, the detection of phase boundary is a key subject and a mathematical model to estimate phase boundary can be formulated in a different manner. Our results indicated that the mesh grouping algorithm is effective to enhance computational performance and image quality, and boundary estimation algorithm to determine the phase boundary directly.

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A Comparison of Image Reconstruction Techniques for Electrical Resistance Tomography (Electrical Resistance Tomography의 영상복원 기법의 비교)

  • Kim, Ho-Chan;Boo, Chang-Jin;Lee, Yoon-Joon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.19 no.3
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    • pp.119-126
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    • 2005
  • Electrical resistance tomography(ERT) maps resistivity values of the soil subsurface and characterizes buried objects. The characterization includes location, size and resistivity of buried objects. In this paper, Gauss-Newton, truncated least squares(TLS) and simultaneous iterative reconstruction technique(SIRT) methods are presented for the solution of the ERT image reconstruction. Computer simulations show that the spatial resolution of the reconstructed images by the TLS approach is improved as compared to those obtained by the Gauss-Newton and SIRT method.

Image Reconstruction of Subspace Object Using Electrical Resistance Tomography

  • Boo Chang-Jin;Kim Ho-Chan;Kang Min-Jae
    • International Journal of Fuzzy Logic and Intelligent Systems
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    • v.6 no.1
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    • pp.47-51
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    • 2006
  • Electrical resistance tomograpy (ERT) maps resistivity values of the soil subsurface and characterizes buried objects. The characterization includes location, size, and resistivity of buried objects. In this paper, truncated least squares (TLS) is presented for the solution of the ERT image reconstruction. Results of numerical experiments in ERT solved by the TLS approach is presented and compared to that obtained by the Gauss-Newton method.

Image Reconstruction of Subspace Object Using Electrical Resistance Tomography

  • Boo, Chang-Jin;Kim, Ho-Chan;Lee, Yoon-Joon
    • 제어로봇시스템학회:학술대회논문집
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    • pp.2480-2484
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    • 2005
  • Electrical resistance tomograpy (ERT) maps resistivity values of the soil subsurface and characterizes buried objects. The characterization includes location, size, and resistivity of buried objects. In this paper, truncated least squares (TLS) is presented for the solution of the ERT image reconstruction. Results of numerical experiments in ERT solved by the TLS approach is presented and compared to that obtained by the Gauss-Newton method.

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Numerical and laboratory investigations of electrical resistance tomography for environmental monitoring

  • Heinson Tania Dhu Graham
    • Geophysics and Geophysical Exploration
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    • v.7 no.1
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    • pp.33-40
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    • 2004
  • Numerical and laboratory studies have been conducted to test the ability of Electrical Resistance Tomography-a technique used to map the electrical resistivity of the subsurface-to delineate contaminant plumes. Two-dimensional numerical models were created to investigate survey design and resolution. Optimal survey design consisted of both downhole and surface electrode sites. Resolution models revealed that while the bulk fluid flow could be outlined, small-scale fingering effects could not be delineated. Laboratory experiments were conducted in a narrow glass tank to validate theoretical models. A visual comparison of fluid flow with ERT images also showed that, while the bulk fluid flow could be seen in most instances, fine-scale effects were indeterminate.

Image Reconstruction with Prior Information in Electrical Resistance Tomography

  • Kim, Bong Seok;Kim, Sin;Kim, Kyung Youn
    • Journal of IKEEE
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    • v.18 no.1
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    • pp.8-18
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    • 2014
  • Electrical resistance tomography (ERT) has high temporal resolution characteristics therefore it is used as an alternative technique to visualize two-phase flows. The image reconstruction in ERT is highly non-linear and ill-posed hence it suffers from poor spatial resolution. In this paper, the inverse problem is solved with homogeneous data used as a prior information to reduce the condition number of the inverse algorithm and improve the spatial resolution. Numerical experiments have been carried out to illustrate the performance of the proposed method.

2D Image Reconstruction of Earth Model by Electrical Resistance Tomography (ERT를 이용한 2차원 대지모델 영상복원)

  • Boo, Chang-Jin;Kim, Ho-Chan;Kang, Min-Jae
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.14 no.7
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    • pp.3460-3467
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    • 2013
  • The In this paper, we have made numerical experiments to compare 2D image reconstruction algorithm of earth model by electrical resistance tomograpy (ERT). Gauss-Newton, simultaneous iterative reconstruction technieque (SIRT) and truncated least squares (TLS) approaches for Wenner and Schlumberger electrode arrays are presented for the solution of the ERT image reconstruction. Computer simulations show that the Gauss-Newton and TLS approach in ERT are proper for 2D image reconstruction of an earth model.

ELECTRICAL RESISTANCE IMAGING OF TWO-PHASE FLOW WITH A MESH GROUPING TECHNIQUE BASED ON PARTICLE SWARM OPTIMIZATION

  • Lee, Bo An;Kim, Bong Seok;Ko, Min Seok;Kim, Kyung Youn;Kim, Sin
    • Nuclear Engineering and Technology
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    • v.46 no.1
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    • pp.109-116
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    • 2014
  • An electrical resistance tomography (ERT) technique combining the particle swarm optimization (PSO) algorithm with the Gauss-Newton method is applied to the visualization of two-phase flows. In the ERT, the electrical conductivity distribution, namely the conductivity values of pixels (numerical meshes) comprising the domain in the context of a numerical image reconstruction algorithm, is estimated with the known injected currents through the electrodes attached on the domain boundary and the measured potentials on those electrodes. In spite of many favorable characteristics of ERT such as no radiation, low cost, and high temporal resolution compared to other tomography techniques, one of the major drawbacks of ERT is low spatial resolution due to the inherent ill-posedness of conventional image reconstruction algorithms. In fact, the number of known data is much less than that of the unknowns (meshes). Recalling that binary mixtures like two-phase flows consist of only two substances with distinct electrical conductivities, this work adopts the PSO algorithm for mesh grouping to reduce the number of unknowns. In order to verify the enhanced performance of the proposed method, several numerical tests are performed. The comparison between the proposed algorithm and conventional Gauss-Newton method shows significant improvements in the quality of reconstructed images.

Performance Comparison of Regularization Methods in Electrical Resistance Tomography (전기 저항 단층촬영법에서의 조정기법 성능비교)

  • Kang, Suk-In;Kim, Kyung-Youn
    • Journal of IKEEE
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    • v.20 no.3
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    • pp.226-234
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    • 2016
  • Electrical resistance tomography (ERT) is an imaging technique where the internal resistivity distribution inside an object is reconstructed. The ERT image reconstruction is a highly nonlinear ill-posed problem, so regularization methods are used to achieve desired image. The reconstruction outcome is dependent on the type of regularization method employed such as l2-norm, l1-norm, and total variation regularization method. That is, use of an appropriate regularization method considering the flow characteristics is necessary to attain good reconstruction performance. Therefore, in this paper, regularization methods are tested through numerical simulations with different flow conditions and the performance is compared.

Three-Dimensional Subsurface Resistivity Profile using Electrical Resistance Tomography for Designing Grounding Grid (접지 그리드 설계를 위한 전기 저항 단층촬영법에 기반한 지표의 3차원 저항률 분포 추정)

  • Khambampati, Anil Kumar;Kim, Kyung Youn
    • Journal of the Institute of Electronics and Information Engineers
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    • v.53 no.4
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    • pp.117-128
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    • 2016
  • Installation of earth grounding system is essential to ensure personnel safety and correct operation of electrical equipment. Earth parameters, especially, soil resistivity has to be determined in designing an efficient earth grounding system. The most common applied technique to measure soil resistance is Wenner four-point method. Implementation of this method is expensive, time consuming and cumbersome as large set of measurements with variable electrode spacing are required to obtain a one dimensional resistivity plot. It is advantageous to have a method which is of low cost and provides fast measurements. In this perspective, electrical resistance tomography (ERT) is applied to estimate subsurface resistivity profile. Electrical resistance tomograms characterize the soil resistivity distribution based on the measurements from electrodes placed in the region of interest. The nonlinear ill-posed inverse problem is solved using iterated Gauss-Newton method with Tikhonov regularization. Through extensive numerical simulations, it is found that ERT offers promising performance in estimating the three-dimensional soil resistivity distribution.