Determination of phases and phase differences of light reflecting from specular or diffusely reflecting, or transparent surface of object

摘要

The method uses light or infrared radiation with rays reflected in a shifting or distorted condition, either from an object with a diffusely reflecting surface, from a transparent object or from the surface of a mirror. The object (10) is irradiated by a coherent beam (11) of known frequency. The reflected rays (12) pass through an imager (13) to a sensor (15). The sensor is composed of many regularly arranged pixels (16). A superimposed reference ray (14) of equal frequency and defined phase produces an speckle interference pattern (17). The intensity values of the pattern are processed to give the calculated phase difference.