3D RECONSTRUCTION OF THE FORT SANTIAGO DUNGEONS USING HANDHELD LASER SCANNING METHOD

Abstract. The preservation of Cultural Heritage sites is an inherent responsibility of the citizens of a country. To this end, developments in digitization serve as a permanent way of preserving a site at its optimum state, and the creation of accurate 3D models becomes a repository of measurements for future reconstruction. Thus, in this study, the Fort Santiago Dungeons, a popular Cultural Heritage site in the Philippines, was 3D-reconstructed using the GeoSLAM ZEB Revo RT, a handheld Light Detection and Ranging (LiDAR) scanner that uses a Simultaneous Localization and Mapping (SLAM) Algorithm. With it, dense point clouds were produced with acceptable results in terms of colorization using the ZEB-CAM accessory, completeness, and measurement noise. This trend extended to quantitative evaluations of the dense point clouds of different formats (LAS and PLY) and colorization settings, as the Root Mean Square Errors (RMSE) against corresponding ground measurements were 0.734cm and 0.739cm for the Non-colorized, and 1.308cm and 1.312cm for Colorized, respectively. Likewise, the derived mesh files gave similar RMSEs with the Non-colorized at 1.044cm (LAS) and 0.999cm (PLY); and with the Colorized at 1.339cm (LAS) and 1.326cm (PLY). Overall, results showed that the mesh file derived from PLY dense point cloud exceeded the other format - as the dungeon's interior was better represented. Nonetheless, even though there were differences in the RMSEs of the measurements, due to factors such as the number of points and the processing itself, all are within the 5cm threshold to be considered useful in the event of reconstruction.