Aerial archaeology is one of the oldest archaeological prospection methods. Although it is highly efficient in detecting sites, its full potential (i.e. the detailed mapping of archaeological and palaeoenvironmental structures) can only be used when the photographs are (ortho)rectified, interpreted and mapped. Georeferencing of the aerial images is commonly determined with ground control points (GCPs), whose measurement and identification is a time-consuming process. It is therefore the biggest bottleneck impeding large-scale archaeological mapping projects with thousands of images.
The general aim of the proposed project is therefore to create automatic solutions for the automated georeferencing and orthophoto generation of archaeological aerial photographs (APs). The resulting workflow should allow the efficient processing of both newly generated and previously acquired aerial images based on available reference data.
In order to fulfil these requirements, the project will (1) evaluate a calibrated digital still camera (DSC) with an attached positioning and orientation system (POS) for archaeological prospection and automated orthophoto production = “hardware approach”; (2) develop a workflow including software for automatic orientation of APs without accurate initial positioning and rotation information = “software approach”. Both approaches will be implemented in the conventional aerial reconnaissance work from a small aeroplane as well as in an innovative method using an unmanned aerial vehicle (UAV) to acquire aerial imagery completely autonomously and being independent of conventional aircraft.
An archaeological case study will serve to test and evaluate all proposed solutions for automated orthophoto generation. The proposed 250 sq km large area is largely covered by vertical and oblique APs from various years and seasons, with scales ranging from 1:25.000 to 1:5.000. The evaluation should identify problems and improve our approach, both using conventional aeroplanes as well as UAVs. The case study should also result in written guidelines about the methods of proper aerial data acquisition and georeferencing. Three international partner organisations (Department of Prehistoric and Medieval Archaeology of the University of Vienna, LBI for Archaeological Prospection and Virtual Archaeology based on an international partnership, Department of Geodesy and Geoinformation (TU Vienna), Research Groups Photogrammetry and Remote Sensing) will co-operate within the project. They have long-term experience in archaeological prospection, especially aerial archaeology and photogrammetry.