Nondestructive testing (NDT) is the process of inspecting, testing, or evaluating
materials, components or assemblies for discontinuities, or differences in characteristics
without destroying the serviceability of the part or system. In other words, when the inspection
or test is completed the part can still be used. Common NDT methods include ultrasonic,
magnetic-particle, liquid penetrant, radiographic, remote visual inspection (RVI), eddy-current
testing,[1] and low coherence interferometry.