说明：  关于摄像标定的一片论文，内容介绍了摄像机标定的过程，以及常见的标定方法：tsai两步法、张正友标定方法。
(In a paper on the camera calibration, the content describes the process of camera calibration, and the common calibration method: tsai two-step method, Zhang Zhengyou calibration.)