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dc.contributor.supervisor LoVetri, Joe (Electrical and Computer Engineering) en_US
dc.contributor.author Zakaria, Amer
dc.date.accessioned 2012-03-27T21:08:42Z
dc.date.available 2012-03-27T21:08:42Z
dc.date.issued 2012-03-27
dc.identifier.uri http://hdl.handle.net/1993/5213
dc.description.abstract This dissertation describes research conducted on the development and improvement of microwave tomography algorithms for imaging the bulk-electrical parameters of unknown objects. The full derivation of a new inversion algorithm based on the state-of-the-art contrast source inversion (CSI) algorithm coupled to a finite-element method (FEM) discretization of the Helmholtz differential operator formulation for the scattered electromagnetic field is presented. The algorithm is applied to two-dimensional (2D) scalar and vectorial configurations, as well as three-dimensional (3D) full-vectorial problems. The unknown electrical properties of the object are distributed on the elements of arbitrary meshes with varying densities. The use of FEM to represent the Helmholtz operator allows for the flexibility of having an inhomogeneous background medium, as well as the ability to accurately model any boundary shape or type: both conducting and absorbing. The CSI algorithm is used in conjunction with multiplicative regularization (MR), as it is typical in most implementations of CSI. Due to the use of arbitrary meshes in the present implementation, new techniques are introduced to perform the necessary spatial gradient and divergence operators of MR. The approach is different from other MR-CSI implementations where the unknown variables are located on a uniform grid of rectangular cells and represented using pulse basis functions; with rectangular cells finite-difference operators can be used, but this becomes unwieldy in FEM-CSI. Furthermore, an improvement for MR is proposed that accounts for the imbalance between the real and imaginary parts of the electrical properties of the unknown objects. The proposed method is not restricted to any particular formulation of the contrast source inversion. The functionality of the new inversion algorithm with the different enhancements is tested using a wide range of synthetic datasets, as well as experimental data collected by the University of Manitoba electromagnetic imaging group and research centers in Spain and France. en_US
dc.subject microwave imaging en_US
dc.subject inverse problems en_US
dc.subject electromagnetics en_US
dc.subject optimization algorithms en_US
dc.title The finite-element contrast source inversion method for microwave imaging applications en_US
dc.degree.discipline Electrical and Computer Engineering en_US
dc.contributor.examiningcommittee Bridges, Gregory (Electrical and Computer Engineering) Lui, Shaun (Mathematics) Pistorius, Stephen (Physics and Astronomy) Bakr, Mohamed (McMaster University) en_US
dc.degree.level Doctor of Philosophy (Ph.D.) en_US
dc.description.note May 2012 en_US


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