中文摘要：

异物入侵铁路线路严重危害行车安全，为及时发现异物并测量其尺寸，提出一种利用相机、异物和线激光空间几何关系计算图像中目标点世界坐标实现异物尺寸检测的方法。相机标定能够得到相机光心与目标点连线的直线方程，线激光投影中的点同时存在于线激光扫描平面和相机光心与该点的连线上。由于钢轨的约束，利用相机标定可以计算钢轨上线激光投影目标点的世界坐标，结合线激光光源坐标标定光平面方程。光平面方程和相机光心与该点连线方程的公共解为目标点的世界坐标。旋转线激光光源，求解异物多个断面关键目标点世界坐标，从而计算异物的三维尺寸。建立测量方法的数学模型并进行现场试验验证，结果表明，该测量方法能够较为准确地测量异物尺寸。

英文摘要：

The foreign objects in the railway lines seriously endanger the traffic safety. To discover and measure the foreign objects, a new size measurement method using the spatial relationship among the camera, the foreign object and the linear laser was presented. Camera calibration can get the line equation of the target and the optical.A point on the linear laser projection is in the light plane and the camera-target line. The world coordinates of light targets on the rails can be calculated using the calibration because of the constraint of the rails. After that,combined with these coordinates and the coordinates of the linear laser source, the scan plane equation is confirmed. The world coordinates of the target points on the foreign objects are the common solutions of the plane equation and the line equation. By rotating the linear laser source, the multiple target points of different foreign object sections are measured to calculate the foreign object size. In this work, the mathematical model of this method was established and was then verified by the field test. The results show that this method can effectively measure the size of the foreign object.