Localization of the Investigation Domain in Electromagnetic Imaging of Buried 2-D Dielectric Pipelines With Circular Cross Section

Abstract

Abstract-Electromagnetic inverse scattering problems are computation intensive, ill-posed and highly non-linear. When the scatterer lies in an inaccessible domain, the ill-posedness is even more severe as only aspect limited data is available. Typical algorithms employed for solving this inverse scattering problem involve a large scale non-linear optimization that generates values for all pixels in the investigation domain including those that might not contain any useful information about the object. This communication is concerned with the localization in the investigation domain prior to inverse profiling of buried 2-D dielectric pipelines having circular cross section. A custom defined degree of symmetry is computed for each transmitter position, which is a measure of the symmetry of the measured (synthetic) scattered field vector. The degree of symmetry vector computed for a scatterer is found to exhibit unique features for the geometric and electric properties of the dielectric pipeline. A probabilistic neural network is trained with the degree of symmetry vectors computed for different object configurations. It classifies the test degree of symmetry vector of the unknown scatterer presented to it into one of the classes that indicate the localized region in the investigation domain in which the pipeline is located. The Distorted Born Iterative procedure is employed for imaging the pipeline that has been localized. The reduction in the investigation domain reduces the degrees of freedom of the inverse scattering problem and the results are found to be much superior to those when the entire investigation domain is employed.

Reconstruction of 2d Pec Targets Using Limited Scattered Information

“…Among all kinds of target detecting theories, the target imaging has received increasing interest because it can provide more particular details in the shape and location of the target than others. The theory of inverse scattering for PEC targets has been well studied since 1965 using the physical optics (PO) approximation [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16]. The most significant contribution to the inverse-scattering theory was established by Bojarski in 1982 [4], where he developed a Fourier transform relationship between the PEC target and the scattered field.…”

Model the Electromagnetic Scattering From Three-Dimensional Pec Object Buried Under Rough Ground by Mom and Modified Po Hybrid Method

“…Modeling the electromagnetic scattering from the object buried under ground has many important applications and has been of interested for a long time [1][2][3][4]. If the ground surface is flat, the Green's function can be formulated with its analytic form by Sommerfeld integral.…”

A Cwa-Based Detection Procedure of a Perfectly-Conducting Cylinder Buried in a Dielectric Half-Space

“…Depending on material properties, the depth of investigation varies from less than a meter to several meters. Processing and interpretation acquired GPR data, it is possible to extract information such as depth, orientation, size and shape of buried objects, density and water content of soils, and much more [10][11][12][13]. The frequencies used in the applications above are chosen to achieve good ground penetration, which necessitates relatively low operating frequencies for typical soils (< 1 GHz).…”