Taking computer vision aloft - Archaeological three-dimensional reconstructions from aerial photographs with PhotoScan

Abstract

Structure from motion (SFM) algorithms are known for their ability to reconstruct a sparse point cloud of scenes that were imaged by a series of overlapping photographs. When complemented by stereo-matching algorithms, detailed three-dimensional models can be built from such photograph collections in a fully automated way. Since 2010, a computer vision software package called PhotoScan has been available from the Russian manufacturer AgiSoft LLC. Even though the programme has a straightforward and simple interface, state-of-the-art SFM and other computer vision algorithms are implemented that enable PhotoScan to generate very dense and accurate three-dimensional meshes of various (archaeological) settings captured in two-dimensional imagery. Using a mixture of archaeological case studies, it will be shown that this low-cost application produces excellent results from aerial imagery in a minimum of time with almost no effort needed. Because of its solid and uncomplicated operation, it looks like this application could become an essential part of the aerial archaeologist’s toolkit.