A general gamma nonlinearity compensation method for structured light measurement with off-the-shelf projector based on unique multi-step phase-shift technology. Issue 15 (2nd September 2019)

• Record Type: Journal Article
• Authors: Cui, Haihua; Jiang, Tao; Cheng, Xiaosheng; Tian, Wei; Liao, Wenhe
• Is Part Of: Journal of modern optics. Volume 66:Issue 15(2019)
• Page Start: 1579
• Page End: 1589
• Publication Date: 2019-09-02
• Subjects: Three-dimensional measurement -- calibration -- phase error correction -- gamma model -- fringe projection profilometry -- structured light measurement -- fringe projection profilometry -- multi-step phase-shift technology -- gamma nonlinearity; Optics -- Periodicals; 535
• DOI: 10.1080/09500340.2019.1648896
• Languages: English
• ISSNs: 0950-0340

Abstract

ABSTRACT: Nonlinearities in the application of fringe projection metrology make it very difficult to acquire perfect 3D data. This paper describes a six-step phase-shifting technique for a structured light measurement system with an off-the-shelf projector. First, the phase error is analysed and a gamma model is established by deriving the relative expression between the wrapped phase and input images. This is then expressed in matrix form to derive a unique solution, which is used for the gamma solver. The complex gamma calibration and projector error compensation can be removed once the gamma value of the off-the-shelf projector has been determined. The ideal model reconstruction results are obtained through simulations and experiments, and the standard deviation of the phase error is found to be only 0.0039 radians. Hence, the proposed method eliminates the nonlinear errors associated with fringe projection technology using existing projectors and improves the overall image reconstruction quality.