Laser-Based Non-Destructive 3D Scanning of Marine Coatings

Optical coherence tomography (OCT) is presented as a field-applicable, non-contact, and non-destructive imaging technique for performing sub-surface inspection of marine coatings. The method is based on broadband mid-infrared supercontinuum laser light to significantly increase the imaging depth and resolution. The OCT system was able to image sub-surface structures, such as cracks and defects, as well as detect substrate corrosion through 369 μm of highly scattering marine coating. The system was also put into the field to show its applicability in an industrial marine environment. OCT imaging therefore has the potential to provide information about the sub-surface coating and substrate environment on marine structures and vessels, which is difficult to achieve using traditional methods.