Michael DONEUS1,2 / Geert. VERHOEVEN1,3 / M. FERA2 / Ch. BRIESE1,4 / M. KUCERA1 / Wolfgang. NEUBAUER1,5
(1LBI for Archaeological Prospection and Virtual Archaeology, Vienna, Austria / 2Department for Prehistoric and Medieval Archaeology, University of Vienna, Austria / 3Department of Archaeology, Ghent University, Belgium / 4Institute for Photogrammetry and Remote Sensing, Vienna University of Technology, Austria / 5VIAS – Vienna Institute for Archaeological Science, University of Vienna, Austria)
Abstract: Stratigraphic archaeological excavations demand high resolution documentation techniques for 3D single-surface recording. Today, this is accomplished using total stations or terrestrial laser scanners. This presentation demonstrates the potential of another technique that is low-cost and easy to implement. It takes advantage of software using Structure From Motion (SFM) algorithms.
SFM algorithms are known for their ability to reconstruct camera pose and three-dimensional scene geometry (rendered as a sparse point cloud) from a series of overlapping photographs captured by a camera moving around the scene. When complemented by stereo matching algorithms, detailed, relatively oriented 3D models can be built from such photo collections in a fully automated way. Because this computer vision approach also works with imagery resulting from a randomly moving camera (i.e. uncontrolled conditions) and calibrated optics are not a prerequisite, the approach is extremely flexible and appropriate to deal with a wide variety of imagery.
Since a few years, such algorithms are embedded in several free and low-cost computer vision software packages. The presentation will outline how these programmes can be applied to map archaeological excavations in a very fast and uncomplicated way, using imagery shot with a normal compact digital camera. In that way, the photographic record of the individual surfaces can be additionally used to create digital surface models and orthophotos. In order to assess the accuracy of the method, the 3D models are compared to simultaneously acquired terrestrial laser scanning data.