Three-dimensional Shape Measurement Using Optimal Number of Phase-shifting Steps Based on Light-source-stepping Method

Abstract

A grating projector using a linear light-emitting diode (LED) array with a grating plate can easily project wideangle, phase-shifted grating patterns. It is optimal for a linear LED array to be placed at an angle to the grating plate in order to maintain the brightness of the grating projection. In this case, the amount of phase shifting significantly varies at each location within the viewing area. Therefore, the authors propose a method to create a map of the optimal number of phaseshifting steps for each pixel and confirm the amount of phase shifting at each position in a grid-projected image. Further, a three-dimensional shape measurement system using a light-source-stepping method is developed. The experimental results obtained with this system using the proposed method confirm that the accuracy obtained using the proposed method is higher than that obtained using the conventional method.