Giacomo Titti (a), Jacopo Turchetto (b) & Giuseppe Salemi (b)
(a) National Research Council, IRPI, C.so Stati Uniti, 35127 Padova, Italy.
(b) University of Padova, Department of Cultural Heritage, Piazza Capitaniato, 35139 Padova, Italy.
Corresponding author e-mail: giacomo.titti@irpi.cnr.it.