振動下で撮影された光干渉像を用いた高精度3次元形状計測

抄録

Vertical-scanning shape-measurement interferometry using white light could not be used under vertically vibrating environment. Because, it is required to repeat predefined-length vertical movement with nanometer accuracy and interferogram capturing just after the movement. We developed the technology which can measure changes of optical path difference (OPD) of an interferometer at around 20-μs interval and can trigger interferogram exposure at even the moment when predefined-length movement complets irregularly due to external vibrations. But vibration during exposure does change interferogram intensities captured. This changes result in phase extraction errors and then shape measurement errors. Then we developed the phase-extraction method which utilizes the history of OPD change during exposure and might remove the above errors. In this paper, validity of this method is estimated by shape-measurement experiments using pulse-like vertical vibrations.