Research On Measurement Method Of The Distance For Crisscross Span Of Overhead Transmission Line Based On Machine Vision

With the development of power grid construction, transmission line corridor resources are becoming more and more serious, and the phenomenon of transmission lines crossing is more and more. It had caused a lot of accidents, which brought great damage to economic operation of power system. Traditional manual detection methods can not guarantee the safe operation of transmission lines. For this, the paper designs a set of on-line monitoring system for crisscross spanning of overhead transmission lines, which presents a new distance measurement method for crisscross spanning based on machine vision. It combines digital image processing and stereo vision measuring technique, can realize real-time monitoring. Experimental results show that the measuring accuracy of this method is within 3%, meets the accuracy requirements. The main work and achievements are summarized as follows:1)It designed a set of on-line monitoring system for crisscross spanning of overhead transmission line based on embedded system design, which can not only realize real-time measuring and fault alarm, but also send the results and actual scene image to monitoring center.2)It studied the image preprocessing and feature extraction methods. It improved the defect of image caused by uneven brightness by using the image enhancement method based on the HSV color model. Because the color image is easily affected by impulse noise, an adaptive vector median filtering method is adopted, which can effectively remove noise and improve image quality. Moreover, the color feature extraction and SIFT feature are provided. And a corner extraction method based on Gauss surface fitting is used, which makes the corner to sub-pixel level.3)It studied a stereo matching algorithm based on SIFT feature and seed growth The algorithm can not only obtain dense disparity map, but also improve the operation speed. And a stereo matching algorithm based on color segmentation and shape recognition is proposed, which can effectively complete stereo marching and make the matching accuracy reach to sub-pixel level.4)A binocular stereo vision measuring system is built. And it accurately realized the distance measurement for crisscross span of overhead transmission line based on constructing the model of the transmission line space curve by reconstructing the 3D coordinate theory. Moreover, it analyzes the effect of different parts on measurement accuracy, and the corresponding improvement measures are given.