Evolution of acoustic feature timing and imaging for different cylinder exposures and applications of reversible SAS filtering

When looking at acoustic scattering from a target near a flat surface, scattering mechanisms exist that may be attributed to interactions with the surface. These different mechanisms can be identified using the timing slope dt/dh, where dh signifies the change in the cylinder exposure. The slopes for the different mechanisms can be determined using ray theory. A technique involving Synthetic Aperture Sonar imaging can be used to isolate acoustic paths scattering directly off the target from those paths which have interacted with the surface after scattering off the target. This method is useful for quickly determining what type of mechanism is involved with a particular path, and in this paper is utilized to verify the identification of slopes. The case studied in this paper is a cylinder near a free surface.