Method or determining phase distributions and differences in light and infrared beams for use in non-destructive testing

摘要

The workpiece (2) is radiated under at least two strains with partially coherent monochromatic light (1), to form images on CCD sensors in a focal plane (5) and superimposed with a reference beam of the same frequency and fixed phase shift. The contrast is determined from the intensity of the speckle pattern. The speckles generate background noise in the focal plane. The method is based on the phase displacement method for analyzing images produce by hologram interferometers. Distribution and difference can be determined from background noise and contrast in a single measurement. An Independent claim is included for a device for performing the method.