Phase invalidity identification framework with the temporal phase unwrapping method

Phase retrieval from fringe patterns is widely used in optical metrology. In profilometry for example, precise phase values allow three-dimensional coordinate data with higher accuracy to be determined. The phase-shifting method coupled with temporal phase unwrapping provides not only the unwrapped phase, but also gives the modulation map, root mean square errors of least-squares fitting, and phase relationship between two neighboring pixels, which can be used for phase error identification. A practical invalid phase identification framework is presented to automatically identify the invalid measuring points with threshold selection and criterion testing. Experimental results show the practical feasibility of the proposed framework.