Experimental study of grating phase-shifting profilometry for body measurement

Based on the fundamental principle of grating phase-shifting algorithm,a low-cost 3-D body measurement experiment system was constructed by digital projector and digital camera.The parallel axis system which can avoid the nonlinear error caused by near core cross-axis system was adopted in combination with projector axis shift and camera local area shooting techniques to expand the effective measurement area.Description of calibration of the system and the design principle of the projection grating were given.The four-step phase-shifting algorithm experiment was carried out for measuring a dummy and the fringe images obtained were processed and calculated,and phase unwrapping was conducted by a second difference region-growing anti-noise algorithm which was optimized by averaging the threshold value to avoid the noise.And finally,the virtual dummy has been constructed by splicing the front and back cloud data.