Principles and applications of emittance-independent infrared nondestructive testing.

Three emittance-independent ir nondestructive testing techniques are described. Two of these use the dual scan ratio principle, and the other uses ir energy reflected from the test specimen surface to compen. sate for emittance differences. Complete details on the theory behind the three techniques are given-Instrumentation used to carry out tests and the results of two practical applications are described.