Authors: Hunter C. Brown and Jeffrey Z. Snyder
L3 OceanServer, Fall River, MA, 02723
Abstract—Seafloor bathymetry was traditionally measured with various mechanical means such as lead-lines or poles, and more recently has transitioned to acoustic methods using single beam altimeters, multibeam sonars, and interferometric sonars. New developments in structure-from-motion software have improved to a level of sophistication where sea-floor bathymetry may be reconstructed using only optical imagery captured from an on-board camera combined with vehicle state information (position, depth, altitude, etc.). In this paper, a camera and strobe system co-located with an interferometric sonar aboard an L3 OceanServer Iver3 Unmanned Underwater Vehicle (UUV) have been used to create seafloor bathymetric reconstructions from photogrammetry. This data was then compared to acoustic bathymetric data from sonar in an effort to quantify the difference between optical and acoustic products. Camera system preparation and altitude effects on both systems are discussed, and individual case studies are presented showing real-world results from both systems.