ONE-STEP PHASE-SHIFT 3-D SURFACE PROFILOMETRY WITH GRATING PROJECTION

A 3-D profiling system has been developed using a grating projection approach and a one-step phase shift algorithm. In the system, a grating pattern projected on an object surface is acquired by a CCD camera, and the grating's phase deformation caused by the surface shape is extracted by spatial phase shift processing, which uses only one frame of digital image. One phase value can be calculated from a successive 3-pixel range if the fringe period is set to either 4-pixel width or 8-pixel width. The fixed phase distribution of the system is excluded by a standard plane calibration. With 8-bit input data, the system's RMS phase accuracy is developed up to 2pi/60 in the experimental examinations.