Development of a physically-based ocean bottom classification analysis system using multibeam sonar backscatter

A physically based mathematical model has been developed to analyze the backscatter intensity from wide swath multibeam sonar systems in order to classify the ocean bottom roughness and sediment type. The input to the model is mosaiced multibeam data corrected for transmission loss (spreading loss and range attenuation), spot size, and local beam-to-bottom incidence angle. Modern image analysis techniques, including geometry driven diffusion and wavelet analysis, are used to segment the corrected, mosaiced backscatter image into regions of limited homogeneity. For each region the authors construct an intensity versus scatter angle curve, which characteristic of the scattering sediment. The curve is then analyzed by a model of backscatter acoustics that takes into account effects of small and large scale roughness of the water-sediment interface as well as volume scattering within the sediment. This analysis yields parameters which characterize the sediment type.