Mathematical models for infrared analysis applied to cultural heritage

Active pulsed infrared thermography is an effective technique consisting in moderately heating the specimen by means of the absorption of a visible light pulse and, then, in detecting the transient variation in the emitted infrared radiation by an infrared camera. Inhomogeneities and buried features eventually located into the specimen volume can be revealed by the recorded infrared images. Such a technique has been successfully applied to the analysis of cultural heritage artifacts like ancient bronzes and manuscripts. The former belong to the category of optically opaque materials, whereas the second to the one of optically semi-transparent materials. For both the two considered categories, a mathematical model for the analysis of the thermographic signal is here presented, together with an implementation in Matlab environment using the finite element technique. The developed models are then used to analyse the experimental results and, hence, to obtain both qualitative and quantitative information about the investigated items.