The Method Of Image Measuring For Sag Of Overhead Transmission Line And Inclination Of Insulator

As two important mechanical parameters of overhead line,conductor sag and insulator angle need to be tested regularly,in order to ensure the safe and reliable operation of the power grid.In this paper,the technology of computer vision and image processing were applied to transmission line inspection,and a method of image measuring for sag of overhead transmission line and inclination of insulator was proposed.The main work is done as follows.First,based on the theory of chain code tracking,realizes the extraction of single lead.In this paper,the edge image is processed by morphological method,which can eliminates the phenomenon of double edge and fracture of the wire effectively.The extraction of single lead was automated by controlling the search direction of the chain code tracking in the case of wire crossing.Second,a new method of sag measurement is realized based on three-dimensional DLT and two-dimensional DLT theory.First,the three-dimensional DLT method was used to solve the projection matrix,and then calculate the two-dimensional space coordinate of sequence points of the conductor by two-dimensional DLT method.The experimental results show that the measurement result is consistent with the actual situation.The method has high measurement accuracy,and has reached the requirements of the engineering application.Third,an improved matching strategies of pyramid is proposed to Distinguish and extract multiple targets automatically.The insulator is extracted according to the shape characteristics of insulator strings.In order to solve the problem of the distortion of insulator,this paper will process the binary image and after processing by morphology by AND operators.In addition,a matching method for insulator end points is proposed.In addition,we present a method of endpoints matching of insulator.Select the central point of the combination of the mandrel and the shed of both ends of insulator as the end-points of insulator.And the accurate matching of the insulator end-points of the two images is realized.Fourth,a method of Image measuring for inclination of insulator based on the theory of monocular vision.First,two images are collected at different locations by camera,which has been calibrated.And then calculate the three-dimensional coordinates of two end-points of insulator using the theory of monocular vision.Last,calculate the spatial angle of the insulator.The experimental results show that the method is simple,implement easily and highly integrated.