Reconstruction of piecewise smooth wave speeds using multiple scattering

Let $c$ be a piecewise smooth wave speed on $mathbb R^n$, unknown inside a domain $Omega$. We are given the solution operator for the scalar wave equation $(partial_t^2-c^2Delta)u=0$, but only outside $Omega$ and only for initial data supported outside $Omega$. Using our recently developed scattering control method, we prove that piecewise smooth wave speeds are uniquely determined by this map, and provide a reconstruction formula. In other words, the wave imaging problem is solvable in the piecewise smooth setting under mild conditions. We also illustrate a separate method, likewise constructive, for recovering the locations of interfaces in broken geodesic normal coordinates using scattering control.