A SLAM-Based Solution to Support ROV Pilots in Underwater Photogrammetric Survey

Survey missions in the underwater environment are key activities in several application fields, but the physical properties of such a harsh environment make it challenging for both navigation and data collection. In particular, in the field of underwater photogrammetry, optical sensors are mainly installed on remotely operated vehicles (ROVs). The maneuvering is performed remotely by expert pilots who can only rely on bidimensional visual feedback from one or more camera streams. Additional navigation data can aid pilots in assessing if the mission meets the requirements while undergoing it. To this end, the paper presents a SLAM-based solution that can be used to compute parameters in support of ROV pilots during photogrammetric surveys, when a stereo-camera is equipped. In order to assess the performance of the proposed solution, different tests were conducted. These tests involved comparing the parameters derived from SLAM with the data computed by the navigation system of a professional-grade ROV. The focus of this comparison was on three key parameters: position, velocity, and distance from the target.