LAITECH Laboratory

Born in 2018 from a collaboration of the Department of Engineering, Economy and Business organization of Tuscia University -in particular the Laboratory of Diagnostics and Materials Science (LABDIAC)- with
Engineering NDT group of Terni (UniPG), Profilocolore S.r.l., Engineering department of University of L’Aquila and the Department of Informatics, Modeling and Electronics and Systems Engineering of University of Calabria.

The mission of the Laboratory research team is to develop an integrated diagnostic method based on innovative non-destructive techniques for paintings investigation. For this purpose, a first research activity, focused on Pulse-Compression Thermography (PuCT) and Hypercolorimetric Multispectral Imaging (HMI), was started both on painting mock-up samples and on real ancient paintings.

HMI enables to gain high-resolution and calibrated digital images in different spectral bands, from ultraviolet (UV) to near infrared (NIR) spectral range (that is 300-1000 nm), in order to get diagnostic information in a rapid and non-invasive way. Relevant hidden data can be obtained from digital image processing (DIP) tools, as most interesting findings can be observed in the combination of different spectral bands and from the application of image processing algorithms such as principal component analysis (PCA), pattern recognition, edge detection and cluster analysis. HMI offers also the possibility to integrate any other imaging data (fluorescence, X-ray, thermal, PuCT) with the multispectral images. It also allows for performing colorimetric measurements and for comparing spectral reflectance data with reference spectra database to build maps of spectral similarity.

HMI investigation of upper painting layer allows to identify painting materials and technique, pentimenti, retouching and ancient restorations. PuCT uses coded low-power heat stimuli and an IR camera to inspect the painting, inducing an instantaneous change in the surface temperature that produces a set of imaging data delayed in time (where more delayed stimulus corresponds with a deeper layer investigated) so to distinguish different layers and materials, as well as discontinuities and defects in a non-destructive stratigraphy. The use of coded modulated heating stimuli with LED chips in combination with pulse-compression
provides a valid aid for painting diagnostic as it permits to investigate artworks without provoking thermochromism effects or other thermal stresses and to achieve a SNR level suitable for the analysis.
In recently completed research activities, the integration of HMI and PuCT imaging data provided an almost complete diagnostic of paintings, providing significant information to best address restoration processes.