Correction of the fringe order errors for fringe projection profilometry

Non-contact three-dimensional (abbreviated as 3D) Fringe projection profilometry (abbreviated as FPP) counts as a method of reconstructing the shape of object surface. This technique has been extensively used in many areas, e.g. computer vision, biomedical research, industrial applications, and virtual reality. Using a FPP, sinusoidal patterns are projected on the object surface by mean of a digital projector, and subsequently a camera captures the reflected patterns deformed by the object surface. As the shape information of the object surface is carried by the deformed patterns, the 3D profile can be retrieved through analysing these patterns. The phase unwrapping is a primary issue bound by the existing phase unwrapping techniques in FPP, aiming to recover the absolute phase from wrapped phase. The temporal phase unwrapping with multi-frequency fringe pattern was proposed, prominently advantaged by none-error propagation. Furthermore, the fringe order is deemed as the critical property to retrieve the absolute phase.