Estimation of Complex Permittivities of Three-Dimensional Inhomogeneous Biological Bodies

Two methods of solving the nonlinear two-dimensional electromagnetic inverse scattering problem in the time domain are considered.These are the Born iterative method and the method originally proposed by Tarantola for the seismic reflection inverse problems. The former is based on Born-type iterations on an integral equation, whereby at each iteration the problem is linearized, and its solution is found via a regularized optimization. The latter also uses an iterative method to solve the nonlinear system of equations. Although it linearizes the problem at each stage as well, no optimization is carried out at each iteration; rather the problem as a whole is posed as a (regularized) optimization. Each method is described briefly and its computational complexity is analyzed. Tarantola's method is shown to have a lower numerical complexity compared to the Born iterative method for each iteration, but in the examples considered, required more iterations to converge. Both methods perform well when inverting a smooth profile; however, the Born iterative method gave better results in resolving localized point scatterers.

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“…In the steepest descent method, the step length a, is found from (10) where (u, , u, ) = u z . C, ' .…”

Section: A'mentioning

confidence: 99%

Comparison of the born iterative method and tarantola's method for an electromagnetic time‐domain inverse problem

Moghaddam

Chew

Oristaglio

1991

Int J Imaging Syst Tech

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“…Second model is used in simulation. Forward problem is solved by using moment-method formulation of electric field integral equation [1][2][3][4][5]. Group theory is applied on matrices to exploit symmetry.…”

Section: Introductionmentioning

confidence: 99%

“…Matrix formulation of electromagnetic problem is given using method of moments in [4]. Microwave imaging of human chest 36-cell model is given with all technical details in [5]. Computation cost of matrix inversion in electromagnetic imaging is reduced by exploiting symmetry using group theory in [6,7].…”

Section: Introductionmentioning

confidence: 99%

Application of Group Theory for Computation Reduction in Microwave Imaging of Human Breast Model at 500 MHZ

Patel¹,

Ghodgaonkar²

2016

PIER M

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Abstract-In microwave imaging, accuracy of breast cancer detection depends on complex permittivity profile reconstruction in breast. Inverse scattering problem is solved to reconstruct complex permittivity profile of breast. In this paper, computation time to solve inverse scattering problem is reduced by exploiting symmetry present in breast models using group theory. Forward problem is solved using method of moments. Levenberg-Marquardt algorithm is used to solve inverse scattering problem with and without group theory. Results show that computation time is reduced considerably by exploiting symmetry present in breast models using group theory. At higher SNR, error in complex permittivity reconstruction with group theory is approximately same as error without group theory.

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“…The images, which showed the internal features of an isolated canine kidney, were obtained by mechanically scanning the body with a pair of antennas and measuring the transmission coefficients between them. Since then, an important effort has been conducted to design systems to measure the scattered fields produced by biological bodies and imaging algorithms adapted to the measurement geometry to reconstruct the permittivity data [61- [14].…”

Section: Introductionmentioning

confidence: 99%

Cylindrical geometry: a further step in active microwave tomography

Broquetas

Romeu

Rius

et al. 1991

IEEE Trans. Microwave Theory Techn.

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-A prototype imaging system for active microwave tomography using cylindrical geometry has been developed, making is possible to obtain images of the dielectric properties of biological targets at 2.45 GHz. The system requires no mechanical movements to illuminate the body from multiple directions (views) and measure the scattered fields. In this way a complete data set consisting in 64 views is acquired in 3 s using low-power illumination. The system is described, including images obtained with biological phantoms and actual bodies.

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Estimation of Complex Permittivities of Three-Dimensional Inhomogeneous Biological Bodies

Cited by 89 publications

References 8 publications

Comparison of the born iterative method and tarantola's method for an electromagnetic time‐domain inverse problem

Comparison of the born iterative method and tarantola's method for an electromagnetic time‐domain inverse problem

Application of Group Theory for Computation Reduction in Microwave Imaging of Human Breast Model at 500 MHZ

Cylindrical geometry: a further step in active microwave tomography

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