Time-Frequency-Space Generalized Coherence and Scattering Functions

The notion of scattering function is commonly used to describe the time-frequency spreading which characterizes the signals distorsion during the propagation in a random medium. For the underwater acoustic channel, the random character is introduced by the roughness of the boundaries (surface and bottom), the inhomogeneities in the volume of water affecting the sound velocity, and the interferences between a large number of rays or modes (particularly in shallow waters).