“…The thermal contrast between defective and non-defective regions is normally weak and potentially degraded by uneven distribution of heat, noise sources, environmental reflections, and variability in the emissivity of the target surface. Therefore, a range of postprocessing algorithms, such as principal component thermography (PCT) [9], thermal signal reconstruction (TSR) [10], and pulsed phase thermography (PPT) [11,12], have been proposed to counteract these factors, and as such to improve the defect detectability in thermographic inspection [13,14].…”