Robot-mounted 500-fps 3-D shape measurement using motion-compensated coded structured light method

Jun Chen, Yongjiu Liu, Qingyi Gu, Tadayoshi Aoyama, Takeshi Takaki, Idaku Ishii

Abstract: A high-frame-rate (HFR) structured light vision is developed for observing moving three-dimensional (3-D) scenes; it is mountable on the end of a robot manipulator for 3-D shape inspection. Our system can simultaneously obtain depth images of 512×512 pixels at 500 fps by implementing a motion-compensated coded structured light method on an HFR camera-projector platform; the 3-D computation is accelerated using the parallel processing on a GPU board. This method can remarkably reduce the synchronization errors in the structured-light-based measurement, which are encountered in the projection of multiple light patterns with different timings; such synchronization errors become larger as the ego-motion of a manipulator becomes larger. We demonstrate the performance of our system by showing several 3-D shape measurement results when the 3-D module is mounted on a fast-moving 6-DOF manipulator as a sensing head.