TOF laser scanner characterization for low-range applications

When TOF laser scanners were introduced on the market, their performances were rather poor, having in general a measurement uncertainty in the range of centimeters. For this reason it was clear that their application was definitely limited to environment and architecture survey, where the large size of the involved objects makes acceptable the relative measurement error. But with the progressive improvement of technology, and the consequent increase in the measurement precision, the potential range of purposes have been widened. In this paper an application to museum objects have been considered. Studying the scanner performance when working at a low range, and using such results to properly interpret the acquired data, it was possible to survey a famous wooden model of S. Peter basilica in Rome, remodeling its shape with a 3D surface modeler. Resolution, precision and accuracy have been studied at distances ranging from 1 to 3 meters, in working conditions similar to those imposed by the museum constrains. The results were used to properly set-up some post processing steps instrumental characterization as a key step in the 3D modeling process, both for increasing the geometrical data reliability, and for processing them (e.g. in the smoothing phase) in a way compliant with their metrological characteristics.