This project aims to develop new means for archaeological coastal mapping and detection, using technologies that are recently becoming affordable, such as Autonomous Unmanned Aerial Vehicles (AUAV or drones). Image Based Methods (IBM) such as Structure from Motion (SfM) and Multi View Stereo (MVS) for 3D recording and documentation are becoming more popular thanks to improved image processing algorithms, while impressive level of detail and precision is attained. Therefore the use of fixed wing UAVs and multicopters for 3D mapping and orthophotos production is widely recognized and becomes accepted as a standard tool for archaeological site documentation or excavation progress monitoring, although there are still limitations and constrains.
Since aerial imagery may penetrate more than 13m in clear Mediterranean waters, coastal archaeological areas could also be benefited by mapping and monitoring using similar techniques. Processing though is not trivial, as the straight rays of light are refracted on sea surface. This affects both the 3D bathymetric model as well as final orthophotomosaic accuracy. The latter is also affected by lack of control points from the sea side, as practice and theory suggest that control points (points of known coordinates) must be measured along the perimeter of the area of interest. This project will propose methods and algorithms to address these problems and streamline the process of creating bathymetric contours, orthophotomosaics on coastal shallow waters for survey, detection, documentation and monitoring of coastal archaeological sites.
Following are a few images from the HawkEye project, involving coastal autonomous UAV orthophomosaic production. The photos show the automatically created contours and the corrected ones, using an approximation model, and check points. Additional details from the orthophomosaic with overlaid contours are shown as an example of the clarity and attained density and quality of the sea bottom.