Abstract of the paper ``Variational constraints for
electrical impedance tomography'' with Robert V. Kohn
The task of electrical impedance tomography is to invert electrical
boundary measurements for the conductivity distribution of a body.
This inverse problem can be formulated so the primary data are the measured
powers dissipated across injection electrodes. Then, since these
powers are minima of the pertinent variational principles (Dirichlet's
or Thomson's principle), feasibility constraints can be formulated for
the nonlinear inversion problem. These constraints may also be used to
stabilize iterative reconstruction algorithms where voltage differences across
other electrodes are the primary data and the measured powers are
treated only as secondary data.
When the powers may be measured accurately, the existence of these dual
variational principles implies that an exact solution (if any) must
lie at a point of intersection of the two feasibility boundaries.
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