Implicit absolute phase retrieval in digital fringe projection without reference lines

Absolute phase retrieval is an important task in many phase-shifting profilometry systems. Most state-of-the-art methods use projection of a reference line on the scene or the codification of code words in the phase domain. In this paper, we propose a novel method based on the generation of constant phase lines. Our method only requires the determination of a strategic pixel on the projector, which is used as the starting point of the unwrapping algorithm. Experimental validation shows that generated phase lines have higher accuracy than the projected reference lines and can be used to obtain the absolute phase map for disconnected objects. (C) 2015 Optical Society of America