Inventors:
James M. Rowe - Torrance CA
Rudolph W. Modster - Los Angeles CA
International Classification:
G01B 902
Abstract:
A speckle pattern interferometer for use in the non-destructive testing of structures employs a laser beam which is split into reference and object beams having substantially the same optical path lengths to the screen of a sensor, such as a vidicon, where the two beams are combined. The object beam is reflected from the surface of an object under investigation, this object being vibrated periodically. The reference beam passes through an optical fiber cut to the proper length to equalize the length of the reference beam path with that of the object beam. The output of the vidicon is fed to an electronic processor where the signals are appropriately processed to provide a speckle pattern display on a monitor viewing screen.