QUALITATIVE AND QUANTITATIVE EVALUATION OF THE LUMINANCE OF LASER SCANNER RADIATION FOR THE CLASSIFICATION OF MATERIALS

Abstract. The main aim of this experimentation is the evaluation of potentialities of terrestrial laser scanner technology to carry-out, beyond topographic and morphological detection, non-invasive materic analysis of the scanned objects, with the prospective to evaluate the conservation of historical landmarks and cultural heritage of which Italy is the world leading country. Coherent lasers in the visible light range may lead to optical diffraction phenomena thus allowing for structural investigation and chemical analysis of the scanned objects. Application of LST in the visible range (λ = 585 nm) to a set of solid samples commonly applied in the construction (building) industry, differing in the crystallinity of their respective lattice, led to the following conclusions: a linear correlation has been established between degree of crystallization of solids and returning luminance of lasers after diffraction onto the solids surface; Gauss distribution of luminance data from diffraction onto less crystalline (plastics, glass) materials has been much narrow than more crystalline ones (metals, alloys, plasters). Both findings confirm that laser diffraction methods may be applied for fast materic determinations after simple LST scanning of solid samples. Bragg modeling of data, extensively applied for Xray diffraction methods (XRD), may be truly co-opted to Laser Scanning.