Calibration for Camera-Motion Capture Extrinsics

Motion capture is commonly used to track the 3D pose of a camera in order to provide accurate ground truth data for computer vision algorithms such as visual odometry, SLAM and object tracking. However, it is challenging to manually align the coordinate frame of a camera and a motion capture-tracked object. This paper proposes a method for estimating the transformation between these two coordinate frames. The suggested approach does not require a special calibration object, instead using the motion capture markers directly. Thus, it has fewer opportunities for human-introduced bias than some existing methods. The proposed method achieves a reprojection error of 7.4px compared to 12.0px for previous work and 84.9px for manual alignment. These results indicate that the proposed calibration method can significantly improve the accuracy of ground truth data obtained from motion capture.