Accuracy assessment of terrestrial laser scanner in heritage documentation

Abstract

Cultural heritage buildings play an important role in reflecting a country’s identity. Recently, governments have directed their attention towards protecting cultural heritage buildings from war, natural disasters, and general wear and tear. In addition to individual countries, international organizations, such as the United Nations Organization of Education, Science and Culture (UNESCO), and its World Heritage Centre, are interested in documenting and preserving historical sites. Based on this increase demand, engineers have been seeking more efficient and cost effective methods to document these cultural heritage sites. Rehabilitation and restoration of heritage buildings depend on being able to accurately record their measurements and details. In the last decade, the field of historic building documentation has developed competition among different surveying techniques systems, and devices for accuracy, cost effectiveness, and overall efficiency. Two of the main documentation techniques are: Digital Close-Range Photogrammetry (CRP) and Terrestrial Laser Scanner (TLS). In this context, the terrestrial laser scanner is the adopted technique in this research, along with investigating all corresponding criteria that govern the final accuracy of the output 3D model. Some of these criteria are the resolution (the ability to detect small objects or object parts in the point cloud) and the quality (which affects the scanning time at fixed resolutions by applying additional noise expression). The current research addresses the optimal recommended combinations of some tested criteria to reach at the most reasonable positional accuracy. Although these criteria are mostly dependent on each other, but certain conditions were set on the scanner for acquiring the best 3D model for any scanned detailed façade.