XIX Sympozjum Srodowiskowe PTZE - materialy.pdf
XIX Sympozjum Srodowiskowe PTZE - materialy.pdf
XIX Sympozjum Srodowiskowe PTZE - materialy.pdf
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<strong>XIX</strong> <strong>Sympozjum</strong> <strong>PTZE</strong>, Worliny 2009<br />
INVERSE APPROACH FOR RECONSTRUCTION<br />
OF CURRENT DENSITY VECTORS<br />
Iliana Marinova, Valentin Mateev<br />
Technical University of Sofia, Department of Electrical Apparatus,<br />
1156 Sofia, 8 Kliment Ohridski St., Bulgaria,<br />
e-mail: iliana@tu-sofia.bg, vmateev@tu-sofia.bg<br />
Abstract<br />
In this paper we apply an inverse approach for 3D current sources reconstruction using measured magnetic field<br />
data. The reconstruction approach is based on the 3D Green’s function of Poisson and Helmholtz equations. The<br />
developed approach was effectively applied for current source distribution reconstruction of coil in linear nonmagnetic<br />
media.<br />
Introduction<br />
Current source distributions in biological structures are extremely important for medical<br />
diagnosis and therapy treatments in various applications.<br />
Magneto CardioGraphy (MCG) and Magneto EncephaloGraphy (MEG) process measured<br />
magnetic field data outside the human body, near the chest or head, for inside current imaging<br />
used for medical diagnoses.<br />
In magnetic stimulation therapy applications, current pulses are supplied to the coil to produce<br />
a strong magnetic field to stimulate nerve fibres. Magnetic stimulation occurs as result of the<br />
current flow and the accompanying electric field induced in the tissue by an externally applied<br />
magnetic field. Determination of magnetic field and current distributions in the tissue in order<br />
to generate prescribed stimulation effect is an inverse source problem.<br />
The current density distribution is basic part in coil design optimisation and electromagnetic<br />
systems syntheses.<br />
In this paper we apply an inverse approach for 3D current sources reconstruction using<br />
measured magnetic field data. The reconstruction approach uses 3D Green’s function. The<br />
magnetic fields are measured in a surface mesh over the tested object region. These data are<br />
used for field source reconstruction in inaccessible for direct measurements region.<br />
The developed reconstruction approach is effectively applied for current source distribution<br />
reconstruction of a circular coil in linear non-magnetic media.<br />
Inverse approach<br />
The magnetic field distribution can be described through the Green’s (1, 2) functions of<br />
Poisson(3) and Helmholtz(4) equations for magnetic vector potential(MVP) and complex<br />
MVP. [1, 4, 5]<br />
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