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Diffraction tomography of strongly scattering infinite cylindrical objects of arbitrary cross-sectional shape
Date Issued
01-01-1990
Author(s)
Jegannathar, S.
Indian Institute of Technology, Madras
Abstract
A new method for imaging an infinite cylindrical object with arbitrary cross-sectional shape, without any small-perturbation approximations, is proposed. In this method, the well-known integral equation equivalent to the inhomogeneous Helmholtz wave equation is discretized. The discretized equation expresses the scattered pressure field at any point in terms of the samples of the product of the unknown object function and the unknown pressure field present inside the object. Based on this relation, simultaneous equations are set up, relating these samples to the samples of the pressure field measured outside the object. By requiring the measurement points to lie on circles around the object, these equations are solved efficiently using the fast Fourier transform (FFT). From the product samples thus obtained, the samples of the unknown object function are extracted by means of a second set of FFT calculations. Details of illustrative computer simulations for the case of an elliptic cylinder are described. © 1990, Acoustical Society of America. All rights reserved.
Volume
88