Computerized geophysical tomography

Dines, K.A.; Lytle, R.J.

doi:10.1109/proc.1979.11390

Cited by 563 publications

(230 citation statements)

References 31 publications

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“…1a and illustrate the results of a classic deterministic inversion algorithm. This method uses a straight ray-based forward model [22], and implements the simultaneous iterative reconstruction technique (SIRT) [56] to minimize the error residuals of the observed and simulated first-arrival travel times. As we are particularly interested in the effect of the number of data points and their measurement error on the inversion results, we use multi-offset profiling with 11 × 11 (top row), 11 × 26 (middle row), and 11 × 51 (bottom row) transmitter-receiver antenna pairs, respectively.…”

Section: Deterministic Inversion Resultsmentioning

confidence: 99%

“…Underground structures tend to be resistive for EM waves, and the propagation velocity of GPR signals depends primarily on the dielectric permittivity of the medium [15,21]. Consequently, firstarrival travel times and a ray-based forward simulator are most often used to reconstruct the structure through inference of the model parameters [22]. This approach is computationally appealing (CPUefficient) and enjoys widespread use due to its affordable modeling errors.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Underground structure defect detection and reconstruction using crosshole GPR and Bayesian waveform inversion

Qin

Xie

Vrugt

et al. 2016

Automation in Construction

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A B S T R A C TCrosshole ground-penetrating radar (GPR) is a widely used measurement technique to help inspect the structural integrity of man-made underground structures, yet the resulting waveform and travel-time data can be difficult, complex and challenging to interpret. Here, we introduce the elements of a Bayesian inversion method for analyzing crosshole GPR data to guide detection of defects (weakness zones) in underground concrete structures. This framework uses as main building blocks the two-dimensional finite-difference time-domain (FDTD) simulator, the discrete cosine transform (DCT) method, and the DREAM (ZS) algorithm to reconstruct the relative permittivity field of an underground concrete structure from full-waveform GPR inversion. The FDTD simulator solves numerically Maxwell's equations in the time and space domain of the crosshole GPR experiment and simulates iteratively the electromagnetic (EM) waveforms. The DCT algorithm transforms the Cartesian parameterization to the frequency domain and reduces drastically the dimensionality of the parameter space by retaining only the low-frequency DCT-coefficients. Markov chain Monte Carlo (MCMC) simulation with the DREAM (ZS) algorithm is used to estimate the posterior distribution of the DCT-coefficients. The usefulness and applicability of the FDTD−DCT−DREAM (ZS) framework is demonstrated on a synthetic test example involving a unit square concrete structure with a small defect. Our results demonstrate that the proposed method successfully detects and locates defects in concrete structures. The inversion results appear rather insensitive to the noise level of the measured GPR waveforms, and the amount of data used (number of receiving antenna positions), as long as a sufficient number of measurements is available. The more DCT-coefficients that are used to characterize the concrete structure, the more accurate the results, yet the larger the posterior uncertainty of the reconstructed permittivity fields.

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Section: Deterministic Inversion Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Underground structure defect detection and reconstruction using crosshole GPR and Bayesian waveform inversion

Qin

Xie

Vrugt

et al. 2016

Automation in Construction

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“…Ultrasonic tomography for nondestructive tests and for characterization of artefacts has been applied in many case with good results [13][14][15][16][17]. In particular, 3D ultrasonic tomography has been recently used to study the structural continuity of the material [18][19][20].…”

Section: Ultrasonic Surveymentioning

confidence: 99%

From Geophysics to Microgeophysics for Engineering and Cultural Heritage

Cosentino

Capizzi

Martorana

et al. 2011

International Journal of Geophysics

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The methodologies of microgeophysics have been derived from the geophysical ones, for the sake of solving specific diagnostic and/or monitoring problems regarding civil engineering and cultural heritage studies. Generally, the investigations are carried out using different 2D and 3D tomographic approaches as well as different energy sources: sonic and ultrasonic waves, electromagnetic (inductive and impulsive) sources, electric potential fields, and infrared emission. Many efforts have been made to modify instruments and procedures in order to improve the resolution of the surveys as well as to significantly reduce the time of the measurements without any loss of information. This last point has been achieved by using multichannel systems. Finally, some applications are presented, and the results seem to be very promising and promote this new branch of geophysics. Therefore, these methodologies can be used even more to diagnose, monitor, and safeguard not only engineering buildings and/or large structures, but also ancient monuments and cultural artifacts, such as pottery, statues, and so forth.

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“…More details can be found in [DBBP1,DBBP2]. It was already mentioned earlier that the method can be considered as a nonlinear generalization of the algebraic reconstruction technique (ART) in x-ray tomography [Nat86], and it is also similar to the simultaneous iterative reconstruction technique (SIRT) as presented in [DL79] or to the Kaczmarz method for solving linear systems of equations (see also [Nat86,NW01]). We will assume for simplicity that the medium is isotropic.…”

Section: Outline Of the Inversion Schemementioning

confidence: 99%

Adjoint Fields and Sensitivities for 3D Electromagnetic Imaging in Isotropic and Anisotropic Media

Dorn

Bertete‐Aguirre

Papanicolaou

2008

Inverse Problems and Imaging

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Summary. In this paper we give an overview of a recently developed method for solving an inverse Maxwell problem in environmental and geophysical imaging. Our main focus is on low-frequency cross-borehole electromagnetic induction tomography (EMIT), although related problems arise also in other applications in nondestructive testing and medical imaging. In typical applications (e.g. in environmental remediation), the isotropic or anisotropic conductivity distribution in the earth needs to be reconstructed from surface-to-borehole electromagnetic data. Our method uses a backpropagation strategy (based on adjoint fields) for solving this inverse problem. The method works iteratively, and can be considered as a nonlinear generalization of the Algebraic Reconstruction Technique (ART) in x-ray tomography, or as a nonlinear Kaczmarz-type approach. We will also propose a new regularization scheme for this method which is based on a proper choice of the function spaces for the inversion. A detailed sensitivity analysis for this problem is given, and a set of numerically calculated sensitiviy functions for homogeneous isotropic media is presented.

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Computerized geophysical tomography

Cited by 563 publications

References 31 publications

Underground structure defect detection and reconstruction using crosshole GPR and Bayesian waveform inversion

Underground structure defect detection and reconstruction using crosshole GPR and Bayesian waveform inversion

From Geophysics to Microgeophysics for Engineering and Cultural Heritage

Adjoint Fields and Sensitivities for 3D Electromagnetic Imaging in Isotropic and Anisotropic Media

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