Baptistery di San Giovanni in Florence - 2014

The laser scanning was performed using a Faro Focus 3D x130 laser scanner with 1–2 mm resolution (FARO 2017). The entirety of the Baptistery was documented using this method (Hess et al. 2018). Fourteen scans were taken on the exterior of the structure at ground level with an average of 28,083,564 points per scan; 13 scans were taken on the interior of the structure at ground level with an average of 43,789,216 points per scan; 21 scans were taken in the upper balcony level with an average of 7,005,528 points per scan; 14 scans were taken in the subterranean level where the wall of interest is with an average of 31,191,672 points per scan (Hess et al.2018). Physical targets were not required for alignment due to the large amount of details on the structure itself; this approach has been proven to be successful in previous literature (Napolitano and Glisic 2018). The scans were aligned using FARO Scene. Initially the scans were positioned by manually identifying mutual features in overlapping scan areas. Subsequently, automatic cloud-to-cloud alignment was utilized to align all scans and reduce any issues from manual registration. To calculate the alignment error, the distance is computed between common points in overlapping point clouds and then averaged for each section; the mean error was 1.2 mm. An image of the laser scan data for the foundation wall can be seen in Figure 3. Additionally, a Canon 5D DSLR was used to augment the existing data set with photographs.
From:

Hess, M., V. Petrovic, M. Yeager, and F. Kuester. 2018. Terrestrial laser scanning for the comprehensive structural health assessment of the baptistery di san giovanni in florence, italy: An integrative methodology for repeatable data acquisition, visualization and analysis. Structure and Infrastructure Engineering 14 (2):. doi:10.1080/15732479.2017.1349810