Calibration of Optical Center Alignment between a High-speed Camera and Galvanometer Mirrors for High-precision Laser Tracking

Controlling laser beam to be directed toward a tracking target with high accuracy is necessary in free-space optical communications and laser processing. If an optical center of a high-speed camera for tracking and a rotational center of a laser scanning system are aligned, three-dimensional calibration becomes unnecessary and wide-area laser tracking projection becomes easier, but it is difficult to precisely align their optical centers only manually. In this paper, we propose an interactive calibration method to precisely align the optical centers using a circular projection on screens with slits on one side, placed in different positions. Image processing visualizes the displacement of the circular parameters on each screen and enables highly accurate alignment in the translational direction. Evaluation experiments have demonstrated sub-pixel accuracy of calibration and fast and accurate laser tracking projection.