Fourier transform profilometry of millimeter-scale surface distortions with added lens setup

Abstract

We apply Fourier transform profilometry to profile surfaces, in millimeter scale distortions, with an added lens in the conventional camera-projector setup. Adding a lens in the setup focuses the projected fringe pattern in the reference plane. This minimizes the problem from the conventional setup that involves the diverging pattern being enlarged as it approach the reference plane. Based from the 2D and 3D surface measurements, we are able to reconstruct the profiles with millimeter scale displacements. Results show that the measured average increment for each displacement produced a 0.50% measurement error. The surface reconstruction with the added lens setup is then compared to the surface reconstruction of the the conventional setup. The conventional setup produced a measurement error of 2.00%. Moreover, more ripple-like structures are observed from the added lens setup. Further investigation should be conducted in order to determine if these structures are part of the canvass or just an error in the reconstruction, and to determine which setup is more accurate. Nonetheless, the obtained values from the measurements tell that Fourier transform profilometry with added lens setup delivers relatively high resolution for surface reconstruction with millimeter-scale distortions.