Camera calibration is a crucial step in photogrammetry and 3D vision applications. In practical scenarios with a long working distance to cover a wide area, target-based calibration methods become complicated and inflexible due to site limitations. This paper introduces a novel camera calibration method using a collimator system, which can provide a reliable and controllable calibration environment for cameras with varying working distances. Based on the optical geometry of the collimator system, we prove that the relative motion between the target and camera conforms to the spherical motion model, reducing the original 6DOF relative motion to 3DOF pure rotation motion. Furthermore, a closed-form solver for multiple views and a minimal solver for two views are proposed for camera calibration. The performance of our method is evaluated in both synthetic and real-world experiments, which verify the feasibility of calibration using the collimator system and demonstrate that our method is superior to the state-of-the-art methods. Demo code is available at https://github.com/LiangSK98/CollimatorCalibration.

本研究针对传统目标基标定方法在长工作距离下的复杂性和不灵活性，提出了一种利用准直仪系统的新相机标定方法。通过光学几何证明，该方法将相机与目标之间的相对运动归结为球面运动模型，并开发了适用于多视图和二视图的封闭式和最小求解器。实验结果表明，该标定方法比现有的最先进方法更具优越性。

利用准直仪系统进行相机标定