volume | PIER Journals

2006-04-03

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

Vinu Thomas,

Dr. Vinu Thomas

Department of Electronics

Cochin University of Science and Technology

India

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Jaimon Yohannan,

Dr. Jaimon Yohannan

Department of Electronics

Cochin University of Science and Technology

India

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Anil Lonappan,

Dr. Anil Lonappan

Department of Electronics

Cochin University of Science and Technology

India

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Gopinathan Nair Bindu,

Dr. Gopinathan Nair Bindu

Department of Electronics

Cochin University of Science and Technology

India

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K. Mathew

Dr. K. Mathew

Department of Electronics

Cochin University of Science and Technology

India

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, Vol. 61, 111-131, 2006

doi:10.2528/PIER05110801

Abstract

Electromagnetic inverse scattering problems are compu- tation 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 ob ject. This communication is concerned with the local- ization 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 scat- terer 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 ob ject configurations. It classifies the test degree of symmetry vec- tor 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 em- ployed for imaging the pipeline that has been localized. The reduction in the investigation domain reduces the degrees of freedom of the in- verse scattering problem and the results are found to be much superior to those when the entire investigation domain is employed.

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Vinu Thomas, Jaimon Yohannan, Anil Lonappan, Gopinathan Nair Bindu, and K. Mathew, "Localization of the Investigation Domain in Electromagnetic Imaging of Buried 2-d Dielectric Pipelines with Circular Cross Section," , Vol. 61, 111-131, 2006.
doi:10.2528/PIER05110801

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