| Transmission lines often pass through inaccessible vast areas,such as virgin forests,rivers and steep mountainous,so manual inspection of transmission lines has been a difficult and laborious task.In recent years,due to the maturity of UAV technology,Using UAVs to inspect transmission lines has been carried out in many places.Although the UAV has facilitated the inspection of transmission lines to an extent,it generates a large number of original pictures instead of defect analysis results.These original pictures depend on manual analysis to detect defects.Because it is a difficult task to analyze the images taken by the UAVs by manual methods,this paper develops a set of visual frames that process the transmission line images taken by UAVs to automatically determine whether there is a defect.Based on the line segment feature extraction of the image,the main work carried out in this paper are:(1)Identify transmission lines and power towers according to the spatial distribution of line segment features;(2)Detect vibration dampers based on the clustering of multiple line segment features;(3)Recognize broken strands by the seed growth method of line segment features;(4)Using the positional relationship between the line segment feature clusters and the transmission lines to identify foreign bodies;(5)Detect the tower rust areas according to the specificity of the tower rust areas in color space;(6)Employ the length and angle distribution histogram of line segment features combined with support vector machine to identify the birds’ nests.In the researches,this paper proposes a line segment connection algorithm based on matrix operations,which can replace the existing loop-based line segment connection algorithm to quickly connect the line segment features of objects;in order to reduce the interference of background,a background filter which can effectively separate the foreground objects from the background and improve the accuracy of recognition is constructed.In the process of recognizing the vibration dampers,the artificial contour line feature generation is proposed to solve the problem that the aside segment features of the vibration dampers cannot be extracted,and therefore improve the recall rate;using the width of the transmission line as the reference length,an automatic adjustment mechanism of the distance threshold parameters is proposed to solve the problem of the fixed thresholds when dealing with different shooting distances and different resolutions. |
