Electricity: measuring and testing – Impedance – admittance or other quantities representative of... – Distributive type parameters
Patent
1997-02-11
1998-11-24
Brown, Glenn W.
Electricity: measuring and testing
Impedance, admittance or other quantities representative of...
Distributive type parameters
324637, 600407, 600430, G01N 2200, G01R 2908
Patent
active
058412883
ABSTRACT:
The invention provides apparatus and methods for determining electric field properties of an inhomogeneous target. The electric property distribution on a coarse mesh discretization of the target is first estimated; and then the electric field on a fine mesh discretization of the target is computed. The fine mesh has finer discretization than the coarse mesh and is overlapping with the coarse mesh. The electric field is then measured at preselected measurement sites within a homogeneous region external to the target. A Jacobian matrix is also calculated which represents a sensitivity calculation relative to a change in the electric field at selected measurement sites due to a perturbation in the electric property distribution on the coarse mesh. A difference vector is formed between the computed electric field and the measured electric field, and an update vector is added to the electrical property distribution as a function of the difference vector and the Jacobian matrix. The electric field is then re-computed based on the updated electric property distribution, which is compared with the measured electric field to produce a least squared error. If this error is not sufficiently small, the steps above, beginning with computing a Jacobian matrix, are repeated until the error is sufficiently small.
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Meaney Paul M.
Paulsen Keith D.
Brown Glenn W.
Microwave Imaging System Technologies, Inc.
Vock Curtis A.
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