基于局部摄影的单目视觉输电线路弧垂测量

Monocular vision transmission line sag measurement method based on local photography

定期监测输电线路中导线弧垂的大小对输电线路的稳定运行有重要意义。传统的弧垂测量方法操作复杂且耗时较长,应用单目视觉获取完整导线图像是一种便捷的弧垂测量方法,但是当输电线路的档距过大时,相机受视场角和分辨率的限制,无法拍摄完整的导线,难以测量弧垂。针对上述问题,设计了一种便捷可用的局部摄影测量方法,将IMU中的加速度计传感器与高分辨率工业单目相机结合,在已知少量输电线路参数的条件下,只需拍摄待测导线的左侧部分即可。获得单幅导线图像后,引入语义分割技术提取图像中的导线,以摄影测量模型为基础将导线的实际点与对应成像点建立联系,以此建立非线性方程组,经非线性求解恢复导线的三维形状,进而计算导线弧垂。弧垂的测量相对误差可以控制在5%以内,满足实际应用需求。

Regular monitoring of the size of wire sag in transmission lines is of great significance for the sta⁃ble operation of transmission lines.The traditional sag measurement method is complex and time-consum⁃ing,and obtaining a complete wire image using monocular vision is a convenient sag measurement meth⁃od.However,when the span of the transmission line is too large,the camera is limited by the field of view angle and resolution,making it difficult to capture the complete wire and measure the sag.To ad⁃dress the above issues,a convenient and usable local photogrammetry method was designed,which com⁃bines the accelerometer sensor in the IMU with a high-resolution industrial monocular camera.With a small amount of transmission line parameters known,only the left part of the tested wire needs to be photo⁃graphed.After obtaining a single wire image,semantic segmentation technology was introduced to extract the wires in the image.Based on the photogrammetric model,the actual points of the wires were connect⁃ed to the corresponding imaging points,and a nonlinear equation system was established.After nonlinear solving,the three-dimensional shape of the wires was restored,and then the wire sag was calculated.The relative error of sag measurement can be controlled within 5%,meeting practical application requirements.