高速列车动态位姿测量方法及校准技术研究

Research on measurement and calibration of dynamic posture of high-speed trains

针对高速列车动态位姿测量中高速、大视场和高精度的测量需求,构建由两台高速相机组成的双目视觉测量系统,通过同步捕捉由大功率线激光瞬时光源构造的测量特征,实现对高速列车动态位姿的实时测量。提出基于非成像模型的相机校准方法,重构相机光学成像过程,构造三维空间成像光束和图像像点之间的一一对应关系,通过建立入射光束角度值与像点坐标的数学模型,实现大视场相机的高精度校准。基于光束平差原理,利用已知长度的基准尺实现双相机位置关系的快速精确校准。实验结果表明,采用上述方法可达到±5"的相机校准精度和±0.2mm的双相机校准精度,整个系统能达到±0.5mm的测量精度,为高速列车动态位姿的测量提供了一种全新有效的手段。

Concerning the many factors, such as high speed, large field of view and high accuracy, which are required in dynamic posture measurement for high-speed train, the binocular vision measurement sys tem is built with two high speed cameras,and the real-time measurement for high-speed train is realized by synchronously capturing features produced by high power pulsed laser. A camera calibration method based on non-linear imaging model has been proposed to reconstruct the optical imaging process and build the relationship between the imaging beams and image points in 3D space. By so doing,the mathe marital model between the angle of incident beam and coordinates of image points has been built and therefore the high-precision camera calibration with large field of view has been gained. Considering a reference meter with a known length,the calibration for the position relationship between the two cam eras is accomplished quickly and precisely with the bundle adjustment algorithm. It is concluded that the precision of camera calibration and that of double-camera calibration can reach ± 5″ and ±0.2 mm, respectively,and this system with the measurement precision of ±0.5 mm proved by experiment results will serve as a new efficient way for the dynamic posture measurement for high-speed train.