Using ultrasound lockin thermography some success has been achieved in detecting varying amounts of hidden corrosion on steel plate. A laboratory test on a steel I beam confirmed that the method was viable.
Further development is needed before moving forward to the supportive artificial intelligence that would be needed for commercial NDT systems incorporating the technology. If verified in commercial terms, and producible in useable and economic forms, this system would have good prospects in all manner of large-scale steel structure inspection, including ships, bridges and storage tanks.
Such equipment would typically be employed to give quantified support in decision making in advance of repair contracts allowing the patch repair method and more effective targeting of limited maintenance budgets across Europe. Depending on costs and technical performance, sales of several 1000s of units per year on a world basis seems realistic.