Absolute phase retrieval methods for digital fringe projection profilometry: A review

This paper provides a review for absolute phase recovery methods that are applicable for digital fringe projection (DFP) systems. Specifically, we present two conventional absolute phase unwrapping methods: multi-frequency or -wavelength phase-shifting methods, and hybrid binary coding and phase-shifting methods; and also introduce some non-conventional methods that are specific for DFP systems: multiview geometry methods with additional camera(s) or projector(s), DFP system geometric constraint-based phase unwrapping method, and pre-knowledge (e.g., computer-aided-design, CAD, model) based phase unwrapping method. This paper also briefly overviews hybrid methods including phase coding, composite, and pre-defined markers based absolute phase unwrapping methods. This paper explains the principle behind each individual absolute phase unwrapping method; and finally offers some practical tips to handle common phase unwrapping artifact issues.