Evaluation of the spatial frequency response and the uncertainty for a commercial structured light system

摘要

Structured light systems (SLS) have become increasingly important for three-dimensional shape measurements. A quantitative evaluation of the spatial resolution is also becoming increasingly important. The spatial frequency response of the instrument is a reasonable metric for resolution and is commonly referred to as the instrument transfer function (ITF). In this paper, we present a methodology to estimate the ITF of a commercial SLS (the EinScan-Pro 3D Scanner) and its uncertainty. A measurement of a step artifact is used for the ITF estimation. We also discuss a method to check the validity of the artifact used for the measurement. The ITF dependence on step orientation and position in the measurement volume is also presented, in addition to a comparison between ITF and the modulation transfer function (MTF) for the cameras in the instrument.