Abstract

In applying optical metrology methods to nondestructive testing applications, a duality of sorts exists between conventional narrow-beam interferometry and holographic interferometry. That is, while a conventional interferometer (e.g., Michelson) can provide displacement measurements at a single point on an object surface for all time, double exposure holographic interferometry provides displacement information over an entire surface at a single instant in time. Unfortunately, the sensitivity with which displacement measurements may be made on diffuse surfaces varies greatly between the conventional and holographic schemes.

© 1990 Optical Society of America