Direct fringe projection profilometry based on the spatial frequency distribution function in optical 3D imaging

Abstract

Phase unwrapping has been a big hurdle in conventional optical three-dimensional (3D) measurement technologies, badly affecting speed and accuracy. To skip the complicated step of phase unwrapping, a direct fringe projection profilometry based on the spatial frequency distribution function is presented in this paper. First, the spatial frequency distribution function is defined according to the physical meaning of spatial frequency. Then, direct phase-shift method and direct Fourier transform profilometry are developed respectively with reference to the conventional fringe projection profilometry. Finally, both numerical simulations and experiments were carried out to test the proposed direct fringe projection profilometry. The direct phase-shift method without phase unwrapping combines the advantages of the conventional in terms of high accuracy, while the direct Fourier transform method does not get rid of the drawbacks of the conventional in spectral aliasing although it skips the phase unwrapping procedure.