Uniaxial fringe projection profilometry using projection defocus

This paper introduces a novel uniaxial fringe projection profilometry (FPP) called active shape from projection defocus profilometry (ASPDP), which utilizes the sharpness analysis of binary fringe patterns to quantify the defocus level. Compared with previous uniaxial FPP methods, our work first utilizes a pinhole defocus model to account for three-dimensional reconstruction. Since defocused fringe pattern can be modeled as the original pattern convoluted with a point spread function (PSF), pixel-wise defocus level can be quantified with this PSFs kernel using temporal Fourier analysis. In this research, calibration is achieved by using a mechanical translation device, and determined by rational polynomial fitting to establish defocus-depth relationship. The experiment demonstrates that this method can provide an accurate reconstructed 3D geometry without shadows.