A fast 3D shape measurement based on two orthogonal grating projection

Abstract

This paper proposes a fast 3D shape measurement method based on two orthogonal gratings projection. Two orthogonal gratings through a beam splitter are vertically projected on an object surface, and the tested object is placed between the imaging planes of the two gratings. Then the image of the object surface modulated by the orthogonal gratings can be obtained by a CCD camera from the same direction. The image is processed by the Fourier transform and spatial frequency domain direction filtering and reverse Fourier transform. Using the modulation distributions of two grating patterns, we can reconstruct the 3D shape of the tested object. In the measurement process, only need to capture one fringe pattern, so it is faster than the previous modulation measurement profilometry, and has also the advantages of vertical measurement without shadow problem. The method provides a possibility to be developed as a new real time pseudocolor encoding system for 3D shape.