Marine Robots Mapping the Present and the Past: Unraveling the Secrets of the Deep

Abstract

Underwater cultural heritage sites are subject to constant change, whether due to natural forces such as sediments, waves, currents or human intervention. Until a few decades ago, the documentation and research of these sites was mostly done manually by diving archaeologists. This paper presents the results of the integration of remote sensing technologies with autonomous marine vehicles in order to make the task of site documentation even faster, more accurate, more efficient and more precisely georeferenced. It includes the integration of multibeam sonar, side scan sonar and various cameras into autonomous surface and underwater vehicles, remotely operated vehicle and unmanned aerial vehicle. In total, case studies for nine underwater cultural heritage sites around the Mediterranean region are presented. Each case study contains a brief archaeological background of the site, the methodology of using autonomous marine vehicles and sensors for their documentation, and the results in the form of georeferenced side-scan sonar mosaics, bathymetric models or reconstructed photogrammetric models. It is important to mention that this was the first time that any of the selected sites were documented with sonar technologies or autonomous marine vehicles. The main objective of these surveys was to document and assess the current state of the sites and to establish a basis on which future monitoring operations could be built and compared. Beyond the mere documentation and physical preservation, examples of the use of these results for the digital preservation of the sites in augmented and virtual reality are presented.

Documenting Maritime Heritage at Risk

“…Airborne LiDAR Bathymetry has been successfully used to generate 3D data from an aerial platform in shallow water using green laser scanning where sonar systems would previously have been used (Wang et al 2020). Marine robots have been used to collate underwater point clouds with photogrammetric models made from drone-captured data (Kapetanović et al 2020). In addition, very recent work using machine learning and neural networks to model from images, as opposed to photogrammetry, suggests that traditional challenges of generating 3D data from reflective surfaces may soon be overcome (Belcore and Di Pietra 2022;Tonion et al 2020).…”

Making the Invisible Visible: Underwater Malta—A Virtual Museum for Submerged Cultural Heritage

“…Remote sensing refers to the use of robotics to investigate the seabed without direct intervention. Underwater robotics are controlled from a boat on the surface and are able to collect large amounts of data in a short period of time, and at depths beyond the diver limit [25][26][27][28]. The generated data has several uses.…”

“…Acoustic shadows are generated behind areas that noticeably rise off the seabed, facilitating the identification of cultural remains. Such an approach allows for high-resolution surveys, providing details on the composition and structure of the seafloor [26,27]. The side-scan sonar utilized for the purpose of this workflow is a dual frequency (600khz/1600khz) EdgeTech side-scan sonar mounted onto an automated underwater vehicle (AUV).…”

Design and Testing of a Spherical Autonomous Underwater Vehicle for Shipwreck Interior Exploration

“…The autonomous vehicles employed may include combinations of unmanned aerial vehicles (UAVs), autonomous surface vehicles (ASVs), and AUVs or ROVs. Kapetanović et al used a multi-system approach to lake bottom bathymetric mapping [17], and cultural heritage sites [18], incorporating an ASV in conjunction with a UAV. A wreck site, discovered in 2007 by the Norwegian Hydrographic Service was later identified in 2015 as the Figaro, a whaling vessel which sank in 1908 [19], using a REMUS 100 AUV, equipped with SSS, in conjunction with a Seabotix LBV 200 ROV, equipped with an HD camera.…”