Active-target-based calibration of relative poses of mirrors in intraoral scanners

This paper describes a practical method using an active target to calibrate relative poses of mirrors in intraoral scanners. Intraoral scanning is a fast-growing technology. Mirrors are widely used in intraoral scanners to increase the measuring area of a single view. The relative poses of these mirrors must be calibrated for accurate three-dimensional profiling. We present and analyze the geometric model of multiview mirrors. A calibration method for relative poses of mirrors is developed based on fringe projection. Vertical and horizontal fringes are displayed on an active target, and every pixel can be viewed as a calibration marker. This calibration method allows the mirrors to have a narrow common field of view. A cell phone display is chosen as the active target, and experimental results demonstrate the effectiveness of the proposed method compared to traditional methods.