Phase unwrapping based on hybrid phase shifting fringes multiplexing for 3D shape measurement

The temporal phase unwrapping (TPU) method is widely adopted for its high measurement accuracy and robustness. However, the existing TPU methods require additional fringe patterns to help determine the phase order, which significantly affects the measurement efficiency and speed. To address this issue, a phase unwrapping method based on hybrid phase shifting fringes multiplexing for 3D measurement is proposed. The method improves the phase shifting fringes by changing the background light intensity of the phase shifting fringes within different periods, thereby embedding period information into the phase shifting fringes. A binary operation is performed on two sinusoidal fringe patterns to obtain periodically distributed phase orders. Subsequently, the period information of different phase shifting fringes is utilized to assist in phase unwrapping, obviating the need for additional fringe patterns. Experimental results confirm that the proposed method can perform phase unwrapping and achieve 3D measurements of objects.