Near-field imaging of inhomogeneities in a stratified ocean waveguide

In this work, we have derived the general representation of the scattered field in the three-layered ocean waveguide. Moreover, a generalized direct sampling method which does not rely on the equivalent condition of density, and a novel MUSIC method as an alternative approach, have been proposed for the reconstructions of penetrable obstacles in the stratified ocean waveguide. In practice, the methods are capable of recovering the scatterers of different shapes and locations, robust against noise, computationally fairly cheap and easy to carry out. We can consider them as simple and fast algorithms to supply satisfactory initial positions for the application of any existing more refined and precise but computationally more demanding techniques to achieve accurate reconstructions of physical features of objects. (C) 2019 Elsevier Inc. All rights reserved.