Preliminary Tests of Millimetric Crack Detection in Ancient Wall Paintings using a Terahertz Radar

Fulvia Gennari, Andrea Campostrini, Agnese Babini, Raffaella Lamuraglia, Giancarlo Ruocco, Valeria Giliberti, Arianna Traviglia, Michele Ortolani
Abstract:
This work investigates the use of a terahertz radar system for the non-invasive diagnosis of wall paintings at the archaeological site of Pompeii. The imaging system is a frequency-modulated continuous-wave radar with a 27 GHz bandwidth centered at 0.3 THz (wavelength ≈ 1 mm), equipped with a pair of Teflon lenses in a confocal configuration and mounted on a robotic arm for XYZ micromovements. Initial tests targeted visible defects such as cracks and detached paint flakes in order to evaluate system performance. By imaging at multiple focal depths, the radar detected not only surface fractures but also possible subsurface extensions and secondary cracks. Also, THz imaging revealed mold and salt efflorescence with millimeter scale resolution. Although 0.3 THz images do not provide material-specific fingerprints, they clearly reveal dielectric contrasts associated with structural anomalies. Overall, the results demonstrate the potential of THz technology for cultural heritage diagnostics and conservation.
Download:
IMEKO-Metroarchaeo-2025-010.pdf
DOI:
10.21014/tc26-2025.010
Event details
IMEKO TC:
TC26
Event name:
TC26 MetroArcheo Conference 2025
Title:

Metrology for Archaeology and Cultural Heritage

Place:
Bergamo, ITALY
Time:
15 October 2025 - 17 October 2025