Monitoring biological degradation of historical stone using hyperspectral imaging

Stone is one of the most common materials used as a building material in central Europe for centuries. Historical objects are endangered by degradation procedures coming from physical, chemical and biological weathering agents.The process itself should be analysed detail order to prevent historical application proper restoration cleaning techniques. Within our research, sandstone block was during time monitor changes on surface. The object interest situated immediate vicinity Charles Bridge Prague, which protected UNESCO heritage site. This site chosen due high overall humidity all year long. For investigation year- round biodegradation hyperspectral sensor used. In first place, data were processed using four vegetation indices (NDVI, RGRI, CRI1 VREI1). All indicate that thriving subject normal seasonal change. second method processing use spectral reflectance curves their subsequence Spectral Angle Mapper (SAM) classification algorithms. A decline with onset autumn winter months detected.