A new phase unwrapping method based on inner-fringe coding

When implementing the phase shifting profilometry to reconstruct the object, phase unwrapping is a critical step when the object with height jump is reconstructed. In this paper, a new method encoding the phase shift value is proposed to unwrap the phase map by two-frequency unwrapping method. Only four fringe patterns are required and the phase value of the low frequency is encoded into the phase shift value of the projected fringe patterns. The effectiveness of the proposed method is verified by the simulations.