QUEST's LOTIS® measurement tools for non-destructive testing (NDT) and gauging are based on the principle of optical triangulation. A laser source similar to a standard laser pointer is directed at the surface whose height is to be measured. An imaging lens collects the light reflected from the surface and focuses it onto a position-sensitive detector. The diagram above illustrates the basic geometry; as the surface height changes, the position of the focused laser spot on the detector moves. The output from the detector is processed electronically to convert the detector positions to accurate height measurements that can be stored on a computer for subsequent display and analysis. This optical triangulation-based technology was originally developed by QUEST to improve the inspection capabilities of U.S. military marine boilers. Since its development in 1987, LOTIS® has been successfully used to inspect thousands of marine boiler tubes. Read more about the implementation of this system at the Navy's Center of Excellence for Ships. Another area where LOTIS® technology has been used is the inspection of heat exchangers for the department of energy. In this Inventions & Innovation Success Story profile, QUEST's LOTIS® system is highlighted.