Benjamin GEHMLICH | Marco BLOCK-BERLITZ
(HTW Dresden, University of Applied Sciences, Dresden, Germany)
Keywords: UAV, 3D reconstruction, SfM, flight strategies
Recently, archaeology has been benefiting much from hardware evolution in UAVs and cameras. Current practice shows two diverging trends that result in different flight strategies. On the one hand, there are experts in remote sensing with very high-quality but heavy cameras. To get these cameras airborne, they need expensive UAVs with sufficient pay-load capacity and flight time. Flight planning software is used to set GPS waypoints for sufficient coverage and overlap of individual, high-resolution images. On the other hand, we see low-cost UAVs in combination with small action cameras being employed by a diversity of archaeological users. In keeping with the spirit of preferring low-cost and open technologies, many archaeologists are also turning to free and open source software for the data processing.
Over the last three years a broad range of sites and areas were UAV-recorded within the scope of the project “Archaeocopter”. These were selected not only due to their historical relevance but also to answer questions about the limits of technical and practical feasibility. Prior to designing different flight strategies, it is reasonable to make oneself familiar with the complexity and diversity of excavation areas and archaeological sites. As a starting point, we examined published remote sensing case studies with a focus on archaeological excavations using UAVs. To this we added our own project work of the last three years, including collaborations with the German Archaeological Institute, the Archaeological Heritage Office in Saxony and other national and international partners. From the resulting knowledge base, we determined three main classes of sites/areas and matching flight strategies for each them. One of the most important aspects in their design was operational safety.
As practical tools, we produced handy instruction cards and an app for android devices, each taking into account the different experience levels of the operators. The cards are freely available on our project page (www.archaeocopter.de). Additionally, training scenarios to improve experience levels are provided.