Self-aligning-calibration of a stereo vision system

Stereo vision system can estimate distance to an object by using 3D information extracted from 2D images of the target. However, since the optical axes of two cameras need to be calibrated simultaneously and aligned in line, the precise estimation of distance is not easy. In view of this, this paper proposes SAC (self-aligning-calibration) method which uses internal and external calibrations for alignment of cameras. The method includes optical encoder and switch for internal calibration and a simple T-calibration device for external correction. In the method, the driving motors of camera system are tuned according to the states of marker and camera angles for exact calibration. The proposed calibration method is applied to a stereo vision system and its effectiveness is shown through real experiments on stereo matching and distance measurement of object.