Convex Obstacles from Travelling Times

We consider situations where rays are reflected according to geometrical optics by a set of unknown obstacles.The aim is to recover information about the obstacles from the travelling-time data of the reflected CITRUS PURE CASTILE SOAP rays using geometrical methods and observations of singularities.Suppose that, for a disjoint union of finitely many strictly convex smooth obstacles in the Euclidean plane, no Euclidean line meets more than Shorts two of them.We then give a construction for complete recovery of the obstacles from the travelling times of reflected rays.