用数码相机测量斜拉桥拉索模型的变形

结合数字近景摄影测量技术的优点及斜拉桥拉索变形的特点,利用普通数码相机对斜拉桥拉索模型的变形进行非接触式测量。考虑到相机光学畸变的直接线性变换,在确定变形平面的基础上,利用单张相片求解目标点物方三维坐标。介绍了实验的整个过程,包括控制点布设、相片拍摄、参数求解、变形平面确定、拉索上目标点变形值计算等。通过对已知点检验证明了用本文方法得到的变形测量精度能满足对桥梁模型进行分析研究的要求。

Measurement of stay cable model deformation of sloping stay bridge using digital camera

In view of the advantages of the digital close shot photogrammetry and the deformation characteristics of the stay cable of the sloping stay bridge,a contactless inspection technique for the deformation of the stay cable model using a household digital camera was proposed.Based on the direct linear transformation accounting for the camera optical distortion,the 3-dimensional coordinates of the target point in the object space can be calculated from a single image if the deformation plane has been determined.The proposed technique was verified experimentally and presented,including the placement of the control points,the image acquisition,the parameters computation,the deformation plane determination,and the deformation calculation of the stay cable target point.It was showed through a comparison with the coordinates of the check points,the precision achieved by the technique is high enough for the measurement in the lab test of the stay cable.