Concepedia

Generic nonsinusoidal phase error correction for three-dimensional shape measurement using a digital video projector

Applied Optics · 2006 · 283 citations · 14 references

TL;DR

Structured‑light 3D shape measurement with digital projectors is common, but the projector’s nonlinear gamma makes fringe patterns nonsinusoidal, causing phase and measurement errors. The study aims to develop a generic LUT‑based phase‑error correction method for any phase‑shifting algorithm. The method generates the LUT by directly analyzing fringe images captured from a flat board. Using a small LUT, the algorithm significantly reduces phase error—experiments show a reduction of at least 13‑fold and demonstrate its applicability to all phase‑shifting schemes.

Abstract

A structured light system using a digital video projector is widely used for 3D shape measurement. However, the nonlinear gamma of the projector causes the projected fringe patterns to be nonsinusoidal, which results in phase error and therefore measurement error. It has been shown that, by using a small look-up table (LUT), this type of phase error can be reduced significantly for a three-step phase-shifting algorithm. We prove that this algorithm is generic for any phase-shifting algorithm. Moreover, we propose a new LUT generation method by analyzing the captured fringe image of a flat board directly. Experiments show that this error compensation algorithm can reduce the phase error to at least 13 times smaller.