Abstract: In the bridge crane payload space positioning system based on monocular vision, in order to solve the problem of matching performance degradation caused by the rotation and tilt of the target template, a real-time bridge crane payloadspace positioning method based on circle detection with vertical gradient direction lines and linear pre-interpolation was proposed. Aspherical target was attached to the top of the payload, and the spherical target was not sensitive to the rotation and tilt when it was detected. First, the spherical target in the Region of Interest (ROI) was detected accurately and fastly by the circle detection method based on vertical gradient direction lines. Secondly, the space coordinates of the spherical target center was confirmed by the space geometry method. And then, the space coordinates were fed back by the method of the linear pre-interpolation. In the contrast experiment with traditional method, space coordinates were transformed to the cable lengths and the payload-swing angles. The experimental results show that the payload-swing angles transformed by this method are more accurate than that of traditional method, and the method can meet the real-time requirement. Moreover, the maximum length measurement error between this method and traditional method is 2.49%, which meets the accuracy requirement.

Key words: monocular vision, space positioning, template matching, circle detection, linear pre-interpolation

摘要： 针对基于模板匹配算法的单目视觉桥吊负载空间定位系统中标识模板旋转、倾斜等造成的匹配性能降低的问题,提出一种结合垂直梯度方向线圆检测与线性预插值的桥式吊车负载实时空间定位方法。该方法通过设置一个附于负载上方的球形标识物, 利用球形标识物在被检测时对旋转和倾斜等情况不敏感的特性, 首先利用垂直梯度方向线的圆检测算法, 对兴趣区域内的球形标识物图像进行精确快速的检测; 再结合空间几何方法对球形标识物球心空间坐标进行计算; 此外, 还使用线性预插值的方法解决了空间坐标的实时反馈问题。通过物理实验, 将空间位置数据转换为负载摆角与吊绳绳长,与传统接触式方法进行对比。实验结果表明,该方法转换得到的摆角数据精确更高,且满足实时性要求;同时,绳长转换数据与接触式方法测得数据误差满足在2.49%以内,满足精度要求。

关键词: 单目视觉, 空间定位, 模板匹配, 圆检测, 线性预插值