General information

Optical Coherence Tomography (OCT), originally developed for biomedical applications, is an interferometric imaging technique that generates high-resolution cross-sectional images of scattering or semi-transparent materials. It employs a light source in the visible or near-infrared spectral range, where the wavelength determines the depth resolution. In Heritage Science, OCT is particularly effective for non-invasive depth profiling of paint layers, offering invaluable insights during restoration processes. This technique is useful for monitoring and documenting micrometric thickness variations in material layers during interventions such as cleaning, which involves the selective removal of deteriorated components like varnishes, oxalates, or overpaints from painted surfaces.

The CNR-INO Heritage Science Group developed the Confocal OCT system. The confocal modality is derived from a confocal microscope that takes advantage of the laser diode and a 2 × 1 fiber coupler to collect both the microscope and the OCT signal, enabling measuring the real thickness of the layers analysed.