Allan Greenleaf, Matti Lassas, Matteo Santacesaria,
Samuli Siltanen and Gunther Uhlmann
Vol. 11 (2018), No. 8, 1901–1943
DOI: 10.2140/apde.2018.11.1901
Abstract
The ill-posedness of Calderón’s inverse conductivity problem, responsible for
the poor spatial resolution of electrical impedance tomography (EIT), has
been an impetus for the development of hybrid imaging techniques, which
compensate for this lack of resolution by coupling with a second type of physical
wave, typically modeled by a hyperbolic PDE. We show in two dimensions
how, using EIT data alone, to use propagation of singularities for complex
principal-type PDEs to efficiently detect interior jumps and other singularities of
the conductivity. Analysis of variants of the CGO solutions of Astala and
Päivärinta (Ann. Math. (2)
163:1 (2006), 265–299) allows us to exploit a
complex principal-type geometry underlying the problem and show that the
leading term in a Born series is an invertible nonlinear generalized Radon
transform of the conductivity. The wave front set of all higher-order terms can be
characterized, and, under a prior, some refined descriptions are possible. We present
numerics to show that this approach is effective for detecting inclusions within
inclusions.