Phase error correction for digital fringe projection profilometry

Non-contact structured light system which utilizes a liquid crystal display (LCD) or digital light processing (DLP) projector is widely used in 3-D surface profile measurement. In such fringe projection profilometry, the digital fringe projection and phase-shifting technique is employed. Although the accurate phase-shifting patterns is generated by a computer and projected by the LCD or DLP projector, the phase measurement error still exists and the error will affect the surface profile measurement results. In this paper, the causes of the phase error are analyzed and the subsequent error corrections are introduced when the color-encoded digital fringe projection (CFP) technique is used to retrieve the phase value. Experimental works are also carried out to verify the effectiveness of the proposed method.