A Methodology for Accurate and Quick Photogrammetric Recording of Underwater Cultural Heritage
Agisoft PhotoScan and other off-the-shelf photogrammetry software became available for archaeologists in 2010; In 2017, after only 7 years, photogrammetry has become a one of the most frequently used recording methods for UCH (underwater cultural heritage) sites. The author of this paper works as a professional maritime archaeologist and applied photogrammetric recording on more than 35 archaeological sites in more than 10 different countries. Because of its submerged circumstances of many shipwrecks, each site has different conditions: such as visibility and colors of waters, depth, topography, water current and so on. Those different conditions create problems that requires different ways to solve those difficulties. Additionally, each project has different mission statement, or project’s goal. For that reason, each submerged site requires different types of methodologies for data-collection and data processing. Moreover, to use produced 3D digital models as archaeological data, it is important to create 1:1 scale-constrained georeferenced 3D models. Yet, to produce these accurate models, it is essential to takes a week to produce local coordinate system that gives scale and georeferenced on the model. To solve these lengthy problem, the author created a methodology that produces local coordinate system in short time (1 or 2 dives) yet provide fairly accurate results. In this paper, the author shall share his methodology of photogrammetric recording that he has developed and currently using.