title: Phase-shifting profilometry combined with Gray-code patterns projection: unwrapping error removal by an adaptive median filter.
abstract: Phase-shifting profilometry combined with Gray-code patterns projection has been widely used for 3D measurement. In this technique, a phase-shifting algorithm is used to calculate the wrapped phase, and a set of Gray-code binary patterns is used to determine the unwrapped phase. In the real measurement, the captured Gray-code patterns are no longer binary, resulting in phase unwrapping errors at a large number of erroneous pixels. Although this problem has been attended and well resolved by a few methods, it remains challenging when a measured object has step-heights and the captured patterns contain invalid pixels. To effectively remove unwrapping errors and simultaneously preserve step-heights, in this paper, an effective method using an adaptive median filter is proposed. Both simulations and experiments can demonstrate its effectiveness.
authors.forename: Dongliang
authors.initials: D
authors.lastname: Zheng
authors.forename: Feipeng
authors.initials: F
authors.lastname: Da
authors.forename: Qian
authors.initials: Q
authors.lastname: Kemao
authors.forename: Hock Soon
authors.initials: HS
authors.lastname: Seah