ASSESSING PATHOLOGIES ON VILLAMAYOR STONE (SALAMANCA, SPAIN) BY TERRESTRIAL LASER SCANNER INTENSITY DATA

Abstract. This paper deals with the assessing of pathologies in façades using a variety of intensity data provided by different terrestrial laser scanner. In particular, a complex building built in the Villamayor Stone that is to be candidate as a Global Heritage Stone Resource has been chosen as study case. The Villamayor Stone were quarrying for the construction and ornamentation of monuments in Salamanca, declared World Heritage City by UNESCO in 1988. The objective of this paper is to assess the pathologies of Villamayor Stone and compare the results obtained through the laser techniques with the classical techniques of mapped pathologies (i.e. visual inspection). For that intensity data coming from laser scanners will be used as non-destructive techniques applied to the façades and several retired plaques (after of building restoration) of Villamayor Stone with pathologies (fissures, scales, loss of matter, humidity/biological colonization) carried to the laboratory. Subsequently it will perform different comparisons between the accuracy reached with the different sensors and a high precision model setup on laboratory which performs as “ground truth”. In particular, the following objectives will be pursued: i) accuracy assessment of the results obtained in in situ and laboratory; ii) an automation or semi-automation of the detection of pathologies in Villamayor Stone; iii) discriminate the different types of Villamayor Stone used in the façades in function of the radiometric response; iv) establish a methodology for detection and assessing of pathologies based on laser scanner intensity data applied to monuments and modern buildings built in Villamayor Stone.