Power Line-Guided Automatic Electric Transmission Line Inspection System

The existing unmanned aerial vehicle (UAV)-based electric transmission line inspection systems generally adopt manual control and follow the predefined path, which reduces the efficiency and makes a high inspection cost. In this article, a UAV system with advanced embedded processors and binocular visual sensors is developed to generate guidance information from power lines in real-time and achieve automatic transmission line inspection. To realize 3-D autonomous perception of power lines, we first propose an end-to-end convolutional neural network (CNN) to extract complementary information from multilevel features and detect power lines with different pixel widths and orientations. Specifically, multilevel feature aggregation module fuses multilevel features within the same stage by learning the weight vector related to the content. The joint attention (JA) module is proposed to extract rich semantic information and suppress the background noises. Meanwhile, multistage detection results are fused to enhance the robustness of the proposed network. Subsequently, power lines are grouped according to the morphological characteristics of thinning detection results, and 3-D point sets of power lines are constructed based on the epipolar constraint of binocular images. Finally, the target point of current stereo images is generated by projecting 3-D power line points to the horizontal and vertical planes. The few-waypoint trajectory is generated based on continuous target points, and automatic inspection is finished with the proposed real-time motion planning strategy. Experimental results on four datasets show that the proposed power line detection method outperforms other state-of-the-art methods. The developed UAV platform and the proposed autonomous inspection strategy are evaluated in practical environments to validate the robustness and effectiveness.