Application of Alford rotation to ground-penetrating radar data

Gestel, Jean‐Paul van; Stoffa, Paul L.

doi:10.1190/1.1487120

Cited by 37 publications

(11 citation statements)

References 23 publications

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“…In this way we can estimate the instantaneous amplitudes as if the antennas have recorded the scattered field with the new orientation. This Alford rotation can produce new images of the two co‐polar or cross–dipole configurations at any angle of orientation (Van Gestel and Stoffa ).…”

Section: Methodsmentioning

confidence: 99%

A multicomponent GPR survey in Marambaia Isthmus

Travassos

André

Musa

2008

Near Surface Geophysics

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This work deals with a multicomponent ground‐penetrating radar data set obtained on Quaternary unconsolidated deposits of eolian, alluvial, lacustrine and marine sands with a choice of two cross‐dipole and two co‐polar antenna configurations. The geophysical response is characterized by strong reflectors observed in both co‐ and cross‐polarized 100 MHz data sets down to a two‐way time (TWT) of 400 ns. With this data set we delineate a given horizon using its overall polarization direction, which is different from that defined by the position of the antennas and of profile direction. That horizon, whose existence was not previously known, represents a more complex situation than an isolated body, e.g., a buried metallic pipe, a situation well studied elsewhere. The polarizing horizon is characterized by linear polarization and a reasonable uniformity of an Alford rotation angle that maximizes the co‐polar responses. With the modal Alford angle we produce improved images corresponding to the two co‐polar components and a conspicuous improvement in the continuity of the reflectors across the polarizing horizon. All goes as if the antennas were oriented parallel and perpendicular to the main polarizing direction of the structure. In addition, the two co‐polar components display a good degree of independence from each other as revealed by their eigenvalues. Our results illustrate how a data set collected with less than optimal field geometry can still satisfactorily reveal the subsurface.

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Section: Methodsmentioning

confidence: 99%

A multicomponent GPR survey in Marambaia Isthmus

Travassos

André

Musa

2008

Near Surface Geophysics

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“…Over the past few years, many theoretical and experimental studies have been carried out to underline the advantages of acquiring multi‐component GPR data (Van Gestel and Stoffa , , ; Radzevicius and Daniels ; Radzevicius et al ).…”

Section: State Of the Artmentioning

confidence: 99%

“…Some authors (Van Gestel and Stoffa , ; Radzevicius and Daniels ; Radzevicius et al ) proposed using the Alford rotation operator to determine the orientation angle of targets which are characterized by directionality. The same method was also used to improve some migration algorithms (Van Gestel and Stoffa ).…”

Section: State Of the Artmentioning

confidence: 99%

GPR multi‐component data analysis

Capizzi

Cosentino

2007

Near Surface Geophysics

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In order to test the capabilities of ground‐penetrating radar (GPR) detection, models were reproduced in a laboratory using both plastic and metal cylinders as well as sheets to represent anomalies buried in a plastic tank containing sand. These models, which represent pipes and dipping layers in a homogeneous medium (i.e., sand), were used to detect the object’s position and study its polarization properties based on the different dielectric contrasts between the object and the surrounding medium. We paid particular attention to the choice of medium through which the wavefield propagated, to be sure of its isotropy and homogeneity, in order for the velocity to be the same for every path travelled. Experimental tests were carried out by changing the dielectric contrasts from the target to the surrounding medium. In particular, the dielectric cylinders (which have a lower permittivity than that of the surrounding sand) were filled with different substances to represent targets such as PVC pipes, either empty or filled with hydrocarbons or water. The resulting scattered field depended on the electrical properties of both the cylinder and the surrounding material, the distance from the cylinder and the scattering angle. Further experimental tests were carried out by using multi‐component GPR data to study the possibility of calculating the angle between the direction of the profile and that of the anomalies. The experimental data obtained as responses to the physical models proved that this method can be successfully applied to detect the orientation of dipping layers, cylinders and vertical fractures.

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“…3,4 This approach produced good results when extracting linearity and orientation features from the late-time response of subsurface unexploded ordnance (UXO) 3 and determining the orientation of geological structures and pipes 4 . In this paper, a frequency domain approach was chosen since experience showed that diagonalization results are easier to interpret when working with scattering matrices that are scaled by the incident field through multiplication rather than convolution.…”

Section: Introductionmentioning

confidence: 97%

Frequency domain analysis of the polarimetric ground-penetrating radar response of landmines and minelike targets

Farinelli

Roth

2003

SPIE Proceedings

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This paper presents a study on using polarimetric ground penetrating radar (GPR) for the identification of plastic antipersonnel mines. In general, the polarimetric radar response of a surface-laid or buried object depends on the orientation of the object with respect to the transmitting and receiving antennas. Hence, in order to make identification possible, it is crucial to measure the full scattering matrix and transform the data into the target frame, in which the response is orientation independent. In this paper, we present an impulse ultrawideband ground penetrating radar with a polarimetric antenna system. Using this radar, the scattering matrices for a set of surface-laid targets with different shape and internal structure have been measured. The measurements were done for different target orientations. Transformation of the measured response into the target frame was achieved by matrix diagonalization in the frequency domain. The eigenvalues obtained by matrix diagonalization constitute a set of orientation invariant features and have been studied as possible target discriminators. In particular, we addressed the problem of classifying targets with respect to shape (rotationally symmetric versus elongated). The results suggest the possibility to distinguish between targets by looking at how the eigenvalues change as a function of frequency. Moreover, matrix diagonalization yielded an angle of orientation and the significance of this angle for small minelike targets and elongated targets is discussed. The analysis was repeated for scattering matrices acquired over buried targets and the results are compared against those obtained for the surface-laid objects.

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Application of Alford rotation to ground-penetrating radar data

Cited by 37 publications

References 23 publications

A multicomponent GPR survey in Marambaia Isthmus

A multicomponent GPR survey in Marambaia Isthmus

GPR multi‐component data analysis

Frequency domain analysis of the polarimetric ground-penetrating radar response of landmines and minelike targets

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