Thermal methods have been recognized above other NDI methods for rapid inspection of large structures. Thermal methods are safe, convenient and relatively inexpensive. Coating tolerant thermography is specifically designed to meet the demands of more challenging field conditions.The technique's ability to differentiate between chipped paint and structural flaws is essential to field performance. However, equally important is the packaging of the system. The system must be lightweight, safe and inexpensive to maintain. This technique utilizes thousands of watts of radiant energy emanating from a hand held system. Inefficiencies in the projection optics can result in heating of the system itself, which then would necessitate significant cooling. This paper describes a unique projection system that can efficiently convert the energy emitted by an inexpensive incandescent line source into several projected stirpes for coating tolerant thermography.
Jon R. Lesniak,
Daniel J. Bazile,
Michael J. Zickel,
"Theory and application of coating tolerant thermography", Proc. SPIE 3361, Thermosense XX, (26 March 1998); doi: 10.1117/12.304743; https://doi.org/10.1117/12.304743