Accurate calibration method for a structured light system

TLDR

Accurate system calibration is essential for reliable 3‑D shape measurement. The study proposes an accurate calibration method for structured‑light 3‑D shape measurement systems. The method treats the projector as a camera, establishes precise pixel correspondences, uses phase‑shifting to generate DMD image sets, and applies a lookup‑table and linear interpolation algorithm to refine projector calibration and 3‑D measurement. Experimental results confirm the improved accuracy of the calibration method.

Abstract

System calibration is crucial for any 3-D shape measurement system. An accurate method is proposed to calibrate a 3-D shape measurement system based on a structured light technique. The projector is treated as a camera to unify the calibration procedures of a structured light system and a well-established stereo vision system. The key to realizing this method is to establish a highly accurate correspondence between camera pixels and projector pixels and generate digital micromirror device (DMD) image sets for projector calibration. A phase-shifting method is used to accomplish this task. A precalibrated lookup table and a linear interpolation algorithm are proposed to improve the accuracy of the generated DMD image, and accordingly improve the accuracy of the projector calibration and the 3-D measurement. Some experimental results are presented to demonstrate the performance of the system calibration.