Feature Extraction Of Power Line Image And Research On The Application Of The Sag Calculation

The sag of transmission line is the key indicator in the design, operation and maintenance, which directly affects the safe and stable operation of lines, so it is necessary to control the value of the sag within the scope of the provisions. In the overhead transmission lines inspection work, in order to calculate real-time and conveniently the sag of the transmission lines, the system of the sag calculation based on sectional power line image analysis is well realized from the angle of image processing in the paper.The plane correction DLT-based method is researched, and the space correction DLT-based method which doesn’t adopt the fixed-points is proposed. Rectify the look up images through the space photography measurement technology, and make its equivalent to just shoot above or in front of the object. The method could have finished the image rectification and does not need cloth any standard fixed-point in the filming site, which could get the real shape of the object.The characteristics of the digital images of the power line are researched, and the special linear characteristics of power line images are fully analyzed, on the base of which a kind of method of using the improved phase consistency to test image features of power lines is put forward. First, the method of phase consistency is researched carefully and improved in the insufficient place. Compared with the traditional detection method, the improved method detects much more accurate power line characteristics. Furthermore, the SURF algorithm is researched and it is optimized to extract the image characteristics. Finally, the edges are thinned and connected to extract a single tag power line.A method of suspension curve model judgment is proposed for sag calculation. According to the extracted parameters three kind of suspension curve model were used to restore complete curve, then it’s determined that the part of power line is more fit for which kind of suspension curve model by the hausdorff distance, which improves the accuracy of sag calculations.The sag calculation method based on sectional power line image analysis is analyzed, which extracts independent variable of the aerial trailer state from sectional power line images, recovers the complete transmission line curve and calculates the sag of overhead lines from certain distance.The paper realizes the sag calculation method based on sectional power line image analysis from the angle of image processing, which provides a quick and effective method for the sag calculation problems in transmission line inspection.