The system was originally developed in the early 1990 for the sub-sea and topside inspections of offshore structures without the need to remove the item's protective coating. Since then it has been successfully applied to onshore process plants and has gained use for inspections of offshore assets. Applications include in-service inspection of welded items and crack detection in vessels. Its main purpose is to evaluate welds in the area of the toe for surface breaking discontinuities such as fatigue cracks.