  In practice of acoustic tomography, for example, in medical applications and
ocean tomography, the relative deviation of sound speed from its background
value usually does not exceed 10-30%. At the same time, in electromagnetic
applications, the equivalent contrasts can be noticeably higher than 60%. Since
the inverse electromagnetic problem can be reduced in some approximation to
Helmholtz equation, a formal comparison of reconstruction results obtained for
different "acoustic" contrast and corresponding "dielectric" contrast is
possible. In this work examples of such reconstructions are presented, which
were obtained by using the functional-analytical algorithm described in works
of R.G. Novikov. Previously, the advantages of this algorithm for solving
practical problems of acoustic tomography were demonstrated. Results obtained
in the present work show that functional-analytical algorithm can also be
applied to reconstructing inhomogeneities with high "dielectric" contrast.
Moreover, the functional algorithm also perfectly reconstructs very small
"dielectric" contrast, recovering of which can be difficult for other
approaches due to weak backscattering.
