为了实现对大型射电天文望远镜的百米远目标进行测量，建立视觉测量系统对目标检测算法、测量系统的稳定性等进行研究。首先， CCD相机获取百米远处反射靶标的图像信息，采用样条函数对靶标图像进行插值，然后用 Canny算法检测靶标图像的边缘信息；接着，采用椭圆拟合算法检测靶标的位置，从而确定靶标在 CCD像面上坐标。采用一个平面标准靶，对检测算法的有效性进行评价。最后，在室外条件下，研究了白天和晚上的时候对靶标进行检测的稳定性。实验结果表明：靶标检测算法可以达到亚像素的测量精度，百米距离靶标测量的稳定性达到 0.08 pixels，基本满足大型射电天文望远镜百米距离坐标测量的需要，具有较强的抗干扰能力。

In order to achieve the 100 meters far away object measurement of large radio astronomical telescope, visual measurement system has been established. The arithmetic of object detection and stability of the measurement system has been researched. First, the CCD camera obtains the image information of the reflected target 100 meters far away. The target image is interpolated by using spline function and the edge information of the target is detected with Canny algorithm. Then, the position of target is measured by adopting ellipse fitting algorithm. Consequently, the image plane coordinates of the target is acquired. The validity of the detection algorithm is appraised by adopting a plane calibration jig. Finally, in the outdoor conditions, the stability of the target measurement is researched at day and night. Experiment results show that the target detection algorithm has the measurement precision of sub-pixel and the stability precision of 100 meters distance target measurement is 0.08 pixels. It can atisfy the 100 meters distance coordinates measurement of large radio astronomical telescope and has better anti-jamming capability.