A Technique to Support the Restoration Activities of Archaeological Discoveries

In this paper the authors propose the use of passive and active thermography to support the restoration of archaeological discoveries. Archaeological restoration is a time-consuming activity entailing high costs. Therefore, the possibility to schedule restoration when it becomes necessary is an important goal. In addition, to guide the restorer on the parts of the archaeological heritage which require urgent maintenance can be a significant support. The proposed technique allows to detect the damaged parts due to material alterations like alveolisation processes, erosions, deposition of iron oxide, defects, fissures, and material irregularities. By evaluating pixel by pixel, the temperature deviation around the known equilibrium value, it is possible to map the material alterations or the parts affected by decay states. Such material alterations are often invisible to the naked eye especially at their onset. This technique allows to highlight the material alterations on the artefact surface by characterizing the emissivity changes. Experimental results on an ancient medallion and on fragments of a marble sarcophagus are reported to prove the relevance of the proposed methodology.