Thermographic survey of frescoes with different thermal stimuli: a PLS-based analysis

Infrared thermography is a well-known technique for the non-destructive evaluation of artworks. In recent times, several image processing algorithms have been proposed and studied to enhance the detection of defects. Amongst them, post-processing methods based on Partial Least Squares (PLS) have shown good results in terms of reliability and detectability of defects. This work analyzes the available PLS-related algorithms for the evaluation of a fresco sample with known defects, stimulated with different heating sources. The results are compared in terms of Signal to Noise Ratio and Receiver Operating Characteristic curves.