针对高层建筑电梯安装过程中导轨垂直度与平行度的要求，设计了一种新型的激光准直系统。该系统把带有同心圆衍射条纹的准直激光束透射过毛玻璃，用CMOS图像传感器作为接收器，获得准直激光束的光斑图像，由USB接口传输到计算机进行自动处理。基于改进的Hough变换算法，完成了同心圆衍射条纹中心的准实时自动提取，并能跟踪、记录条纹中心的变化轨迹。该系统可以在128 mm×96 mm的范围内接收准直激光束的圆衍射条纹，条纹中心提取精度在1～2个像素，很好地满足了实际应用的要求。

In view of the requirements of the verticality and parallelity in the process of equipping elevator for high building, a new laser collimating system is presented. In this system, the laser collimating beam is transmitted through the frosted glass with concentric circles diffraction fringes. The image can be captured by using CMOS sensor, and can be processed automatically when it is carried into computer by USB I/O. Based on developed Hough transform algorithm, the center of concentric circles diffraction fringes can be automatically acquired and tracked in real-time condition. The track graph is depicted out in the subsidiary window. The circle diffraction fringe can be received in the range of 128 mm×96 mm, and the precision of center coordinates is about 1 or 2 pixels. It is proved that the method can greatly satisfy the application requirement.