TESTING OF CLOSE-RANGE PHOTOGRAMMETRY AND LASER SCANNING FOR EASY DOCUMENTATION OF HISTORICAL OBJECTS AND BUILDINGS PARTS

Abstract

In contemporary times, technology has dramatically simplified the process of documenting cultural heritage objects. This paper aims to illustrate modern methodologies for documenting historical monuments by applying advanced technologies, as these case studies show. Two technologies were used: laser scanning and digital photogrammetry. The first subject of our study was a historically significant 16th-century building located in Jachymov, situated in the North-West region of the Czech Republic. The object was documented by laser scanning (BLK360) and using a standard digital camera Canon Powershot SX230 HS. The laser scanning data were post-processed using Cyclone Register 360 Plus, while photogrammetric point clouds were generated with Agisoft Metashape. The second objects were a building and a sculpture in the historical UNESCO city of Telč; here laser scanning instruments, digital photogrammetry and a new one low-cost ViDoc documentation system were use. Our study is focused on analyzing the sets of point clouds obtained from the data processing, conducted using CloudCompare to draw insights and conclusions. It turns out that the rapid development of techniques and technology makes it possible to use low-cost devices for sufficiently accurate and fast documentation; however, the mentioned ViDOC device can only be used for very close and small objects up to about 5 meters. For the documentation of sculptures, classic close-range photogrammetry is especially appropriate; for the documentation of buildings, laser scanners are suitable; the problem here is with hidden spaces and it is often necessary to use either a platform or a combination with photogrammetry using a drone, especially for the upper parts of the object.