Armand Wirgin – författare

This book presents current research trends in the field of underwater acoustic wave direct and inverse problems. Until very recently, little had been published concerning model-based inversions of the boundaries and material constants of finite-sized targets located in either the water column or the sediments. This text is the first to investigate inverse problems in an ocean environment, with a heavy emphasis placed on the description and resolution of the forward scattering problem.Marine Acoustics emphasizes computation of Green's Functions with new material added for elastic and poro-elastic seabeds. This timely publication addresses many areas of practical interest related to underwater acoustical imaging, including ecological survey and cleanup, protection of open water harbors, maintenance of offshore petroleum and gas enterprises, and other areas of environmental and military concern.The ocean-seabed system is an acoustic waveguide, and this is the only book that treats inverse problems in a waveguide. The propagation of acoustic waves in this system is treated for various types of seabeds and the direct and inverse problems are considered in realistic ocean environments. The inverse problem is to determine the shape of an impenetrable or penetrable object, or to determine the coefficients describing the seabed. This is done by acoustically illuminating the seabed and investigating the scattered field.

This book provides an up-to-date presentation of a broad range of contemporary problems in inverse scattering involving acoustic, elastic and electromagnetic waves. Descriptions will be given of traditional (but still in use and subject to on-going improvements) and more recent methods for identifying either:a) the homogenized material parameters of (spatially) unbounded or bounded heterogeneous media, orb) the detailed composition (spatial distribution of the material parameters) of unbounded or bounded heterogeneous media, orc) the location, shape, orientation and material characteristics of an object embedded in a wellcharacterized homogeneous, homogenized or heterogeneous unbounded or bounded medium, by inversion of reflected, transmitted or scattered spatiotemporal recorded waveforms resulting from the propagation of probe radiation within the medium.

This book provides an up-to-date presentation of a broad range of contemporary problems in inverse scattering involving acoustic, elastic and electromagnetic waves. Descriptions will be given of traditional (but still in use and subject to on-going improvements) and more recent methods for identifying either:a) the homogenized material parameters of (spatially) unbounded or bounded heterogeneous media, orb) the detailed composition (spatial distribution of the material parameters) of unbounded or bounded heterogeneous media, orc) the location, shape, orientation and material characteristics of an object embedded in a wellcharacterized homogeneous, homogenized or heterogeneous unbounded or bounded medium, by inversion of reflected, transmitted or scattered spatiotemporal recorded waveforms resulting from the propagation of probe radiation within the medium.