Mathematical models for infrared analysis applied to cultural heritage

Pulsed active infrared thermography is an effective technique consisting in slightly 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 means of 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 manufacts like ancient bronze statuary and manuscripts. The former belong to the category of optically opaque materials, whereas the second to the category 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.