Roughness Spectra and Acoustic Response from a Diver-Manipulated Sea Floor

A digital stereo photogrammetric system was designed and implemented to measure seafloor roughness in coastal sands. High-resolution images that achieve more than four pixels/mm in either the horizontal or vertical dimension are created by two cameras sealed in watertight housings and actuated simultaneously by a scuba diver. A Digital Elevation Model (DEM) of the photographed sea floor is created from digital autocorrelation of left and right paired images. The DEM is used to estimate a 2D roughness power spectrum, from which are derived parameters of the spectral exponent and spectral strength that are used as inputs in high-frequency acoustic scattering models