Electromagnetic Imaging Methods for Nondestructive Evaluation Applications

Deng, Yiming; Liu, Xin

doi:10.3390/s111211774

Cited by 92 publications

(43 citation statements)

References 109 publications

(111 reference statements)

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“…The outside pole is set at O 2 , the centre of spherical surface Γ 2 . The solution to the Laplace Equation (6) in the valid domain is given as follows [4,7,8]:

\begin{array}{l} left & W & = A + \sum_{l = 1}^{N_{l}} r_{i}^{l} false(A_{i}^{l} P_{l} false(cos θ_{i} false) + \sum_{m = 1}^{l} P_{l}^{m} (cos θ_{i}) (A_{i}^{lm} cos m α_{i} + B_{i}^{lm} sin m α_{i}) false) + \sum_{p = 1}^{N_{p}} [\frac{A_{op}}{r_{op}} + \sum_{l = 1}^{N_{op}} r_{italicop}^{- false(l + 1 false)} false(A_{italicop}^{l} P_{l} false(cos θ_{italicop} false) + \sum_{m = 1}^{l} P_{l}^{m} (cos θ_{i}) (A_{op}^{lm} cos m α_{op} + B_{op}^{lm} sin m α_{op})) \\ left & = \sum_{k = 1}^{N} α_{k} U_{k} \end{array}

where

r_{i} = | \overset{true\to}{r} - \overset{true\to}{r_{i 1}} |

\overset{true\to}{r_{i 1}}

…”

Section: Electromagnetic Modeling Of the Sensormentioning

confidence: 99%

Electromagnetic Field Analysis and Modeling of a Relative Position Detection Sensor for High Speed Maglev Trains

Xue

2012

Sensors

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The long stator track for high speed maglev trains has a tooth-slot structure. The sensor obtains precise relative position information for the traction system by detecting the long stator tooth-slot structure based on nondestructive detection technology. The magnetic field modeling of the sensor is a typical three-dimensional (3-D) electromagnetic problem with complex boundary conditions, and is studied semi-analytically in this paper. A second-order vector potential (SOVP) is introduced to simplify the vector field problem to a scalar field one, the solution of which can be expressed in terms of series expansions according to Multipole Theory (MT) and the New Equivalent Source (NES) method. The coefficients of the expansions are determined by the least squares method based on the boundary conditions. Then, the solution is compared to the simulation result through Finite Element Analysis (FEA). The comparison results show that the semi-analytical solution agrees approximately with the numerical solution. Finally, based on electromagnetic modeling, a difference coil structure is designed to improve the sensitivity and accuracy of the sensor.

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“…The outside pole is set at O 2 , the centre of spherical surface Γ 2 . The solution to the Laplace Equation (6) in the valid domain is given as follows [4,7,8]:

\begin{array}{l} left & W & = A + \sum_{l = 1}^{N_{l}} r_{i}^{l} false(A_{i}^{l} P_{l} false(cos θ_{i} false) + \sum_{m = 1}^{l} P_{l}^{m} (cos θ_{i}) (A_{i}^{lm} cos m α_{i} + B_{i}^{lm} sin m α_{i}) false) + \sum_{p = 1}^{N_{p}} [\frac{A_{op}}{r_{op}} + \sum_{l = 1}^{N_{op}} r_{italicop}^{- false(l + 1 false)} false(A_{italicop}^{l} P_{l} false(cos θ_{italicop} false) + \sum_{m = 1}^{l} P_{l}^{m} (cos θ_{i}) (A_{op}^{lm} cos m α_{op} + B_{op}^{lm} sin m α_{op})) \\ left & = \sum_{k = 1}^{N} α_{k} U_{k} \end{array}

where

r_{i} = | \overset{true\to}{r} - \overset{true\to}{r_{i 1}} |

\overset{true\to}{r_{i 1}}

…”

Section: Electromagnetic Modeling Of the Sensormentioning

confidence: 99%

Electromagnetic Field Analysis and Modeling of a Relative Position Detection Sensor for High Speed Maglev Trains

Xue

2012

Sensors

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“…Imaging piecewise homogeneous objects is of interest in various applications in non-destructive testing [4] and subsurface sensing [5]. Several spatial smoothing techniques have been proposed to enhance edges in nonlinear inverse scattering algorithms, e.g., L1-norm total variation (TV) regularization [6], edge-preserving regularization [7] with weighted L2-norm TV [8] and with various potential functions [9], [10].…”

Section: Introductionmentioning

confidence: 99%

Piecewise Smoothed Value Picking Regularization Applied to 2-D TM and TE Inverse Scattering

Bulcke

Franchois

Zutter

2013

IEEE Trans. Antennas Propagat.

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The Stepwise Relaxed Value Picking (SRVP) regularization technique, proposed earlier for the iterative reconstruction of piecewise (quasi-)homogeneous objects, is a non-spatial technique, whereby the reconstruction unknowns are clustered around a limited number of-a-priori unknown-reference values. Artifacts have been observed in some 2-D and 3D complex permittivity reconstructions. This paper therefore combines the non-spatial SRVP technique with a spatial smoothing technique, whereby the reference values provided by the former-in each iteration-are employed by the latter to define separate smoothing regions. This way edges are preserved, since the spatial smoothing constraints in the cost function are active within but not across the region boundaries. This combined technique, denoted as Stepwise Relaxed Piecewise Smoothed Value Picking (SRPSVP) regularization, is formulated for the 2.5D microwave inverse scattering problem and is illustrated with reconstructions from the Institut Fresnel 2-D scattering database.

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“…The more consolidated applications perhaps are those related to the use of ground penetrating radar, but a lot more are at present used or in advanced state of development. For example, it has been suggested that microwave imaging could be successfully used as a diagnostic technique in several areas, including civil and industrial engineering [3][4][5], nondestructive testing and evaluation [6][7][8][9], geophysical prospecting [10], and biomedical engineering [11][12][13][14]. Microwave imaging has also been proposed as a useful tool in wood industry [15].…”

Section: Introductionmentioning

confidence: 99%

Location and Shape Reconstruction of 2D Dielectric Objects by Means of a Closed-Form Method: Preliminary Experimental Results

Gragnani

Mendez

2012

International Journal of Microwave Science and Technology

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An analytical approach to location and shape reconstruction of dielectric scatterers, that was recently proposed, is tested against experimental data. Since the cross-sections of the scatterers do not depend on the z coordinate, a 2D problem can be formulated. A closed-form singular value decomposition of the scattering integral operator is derived and is used to determine the radiating components of the equivalent source density. This is a preliminary step toward a more complete solution, which will take into account the incident field inside the investigation domain in order to provide the dielectric features of the scatterer and also the nonradiating sources. Reconstructions of the equivalent sources, performed on some scattering data belonging to the Fresnel database, show the capabilities of the method and, thanks to the closed-form solution, results are obtained in a very short computation time.

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Electromagnetic Imaging Methods for Nondestructive Evaluation Applications

Cited by 92 publications

References 109 publications

Electromagnetic Field Analysis and Modeling of a Relative Position Detection Sensor for High Speed Maglev Trains

Electromagnetic Field Analysis and Modeling of a Relative Position Detection Sensor for High Speed Maglev Trains

Piecewise Smoothed Value Picking Regularization Applied to 2-D TM and TE Inverse Scattering

Location and Shape Reconstruction of 2D Dielectric Objects by Means of a Closed-Form Method: Preliminary Experimental Results

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