Hyperspectral imaging coupled with 3D recording as a tool for the preventive conservation of historic houses

In the context of climate change, castle museums are facing the challenges posed by rapid weather fluctuations which can lead, for example, to the sudden deterioration of murals or tapestries. It therefore seems necessary to enhance the existing tools for monitoring and measuring early signs of deterioration with new, state-of-the-art multidimensional analysis instruments to serve as a decision-support system for preventive conservation strategies. To this end, a system combining hyperspectral imaging (HSI)—covering both the visible and short-wave infrared spectra—with 3D LiDAR scans was implemented at the Palace of Versailles, in the Queen’s Bedroom and the Mercury Salon, for seasonal measurements. A sample of representative elements was first selected for each room using the EPICO (European Protocol In preventive COnservation) method, then closely monitored over the course of the seasons for more in-depth analysis. Once per season, three sets of data are collected for each designated artwork: visible, infrared, and 3D data. This allows us to track their changes based on their nature and weather conditions. To date, four seasons have already been covered: summer (July 2025), fall (November 2025), and winter (February 2026), and spring (May 2026). The goal is to identify the links between these environmental measurements and the condition of the objects in situ; a comprehensive and individualized understanding of how these objects evolve is necessary to hope to understand the cause-and-effect relationships. The scientific challenge is to create a three-dimensional map of the physical characteristics of spaces and objects and to monitor them, from the molecular to the structural scale. This HyperPICO project is supported and funded by the Fondation des Sciences du Patrimoine. The new gonio-hyperspectral system, consisting of two cameras covering the 400–1700 nm spectrum (VIS-SWIR) and a LiDAR for geospatial information, is funded as part of the Equipex+ Espadon