Crystal based fringe generator system

摘要

A measurement system (10) for accurately measuring the surface geometry of a part (32) in three dimensions includes a laser (12) for emitting a laser beam (14). The laser beam (14) is transmitted to a birefringent crystal (16) which splits the laser beam (14) into a pair of beams (18,20). The pair of beams (18,20) are then subjected to a phase shift by a liquid crystal system (24) as controlled by a computer (26). The pair of beams (18,20)are then expended in order to form a fringe pattern (30) on the surface of the part (32) to be measured.