Profilometry with digital fringe-projection at the spatial and temporal Nyquist frequencies

TL;DR

This paper introduces a phase-demodulation method for digital fringe-projection profilometry that operates at the highest spatial and temporal Nyquist frequencies, enabling high-sensitivity 3D surface digitization without complex filtering.

Contribution

It presents a novel approach that uses the highest Nyquist frequencies for spatial and temporal sampling, eliminating the need for spatial low-pass filtering and gamma calibration.

Findings

Achieves high sensitivity in 3D surface digitization.

Effectively rejects DC component and even harmonics with minimal phase shifts.

Experimental results confirm the method's accuracy and robustness.

Abstract

A phase-demodulation method for digital fringe-projection profilometry using the spatial and temporal Nyquist frequencies is presented. It allows us to digitize tridimensional surfaces using the highest spatial frequency ({\pi} radians per pixel) and consequently with the highest sensitivity for a given digital fringe projector. Working with the highest temporal frequency ({\pi} radians per temporal sample), the proposed method rejects the DC component and all even-order distorting harmonics using a bare-minimum 2-step phase shift. The proposed method is suitable for digitization of piece-wise continuous surfaces because it does not require spatial low-pass filtering. Gamma calibration is unnecessary because the projected fringes are binary, and the harmonics produced by the binary profile can be easily attenuated with a slight defocusing on the digital projector. Viability of the proposed method is supported by experimental results showing complete agreement with the predicted behavior.