Detachments detection at the ‘Grand Stairway’ in the Room 38 of the Domus Aurea using the PICUS system

• Automatic detection of detachments in a large fresco. • The comparison between the manual and automatic map is verified. • The PICUS map use a colorimetric scale highlighting accurately the detachments. • A single operator maps large areas of the fresco in a short time. • The method revolutionizes the approach to detection and analysis of defective areas. The purpose of this research was the diagnosis of the detachments and the analysis of the subsequent stabilization intervention of antique roman plaster in Room 38 of the Domus Aurea . We carefully assessed the extent of the detachments in the fresco-decorated plaster before initiating the stabilization intervention. Two methods were implemented: manual auscultation and automatic scanning using the PICUS system. Both produced a map representing the defects prior and after the intervention. The comparison between the map obtained by the auscultation method and the PICUS map shows that they can be superimposed. The map obtained with the PICUS system highlights the most severe defects using a colorimetric scale, which is normally not used in a manual scan. The PICUS system has proven to be a valid support to the classical manual auscultation to prepare the map of the defects of antique, damaged cultural heritage.