Research On Intelligent Detection And Application Method Of Railway Line Based On Mobile Scanning Measurement System

The continuous improvement of railway network provides convenience for travelling.At the same time,the high-density and large volume of railway transportation challenges railway engineering.Workers are required to complete the detection of railway in a short time in various natural environments.In order to overcome the shortcomings of traditional detection,such as low efficiency,poor safety and discrete measurement data,this thesis applies mobile scanning measurement system to obtain point cloud data of railway quickly and efficiently in real time,and design a fast,accurate and systematic processing method for massive point cloud data so as to realize integrated and intelligent detection of railway.Therefore,this thesis focuses on the data acquisition and application of mobile scanning measurement technology in detection of railway:(1)Rail segmentation algorithm based on region growing of intensity and fast extraction algorithm of point cloud data of rail top surface with various constraints.According to the intensity,geometric dimension and continuity of rail,a region growing segmentation algorithm based on intensity is proposed,which can quickly obtain point cloud data of rail from massive point cloud data.Based on the segmented point cloud data of rail,the point cloud data of rail top surface can be extracted quickly with the constraints of point height similarity,intensity consistency and point density uniformity of rail top surface.(2)The extraction algorithm based on point cloud data of coordinate of railway mid-line points and detection method of track geometry size.With the help of differential idea,point cloud of the rail top surface is segmented,and the top mid-line equation of the left and right rails in a single point cloud segment is fitted.The coordinate of mid-line point in each point cloud segment is calculated in turn to realize the automatic extraction of coordinate of railway mid-line points.Based on the data of rail point cloud and rail top surface midpoint,the measurement method of track geometry(gauge,level,height and direction)is studied,and part of rail point cloud is selected for the test of track geometry.(3)The algorithm of obtaining the plane line feature parameters based on the coordinate of mid-line pointsBased on the coordinate of mid-line points,according to the equal interval sampling method,combined with the variation law of the slope of the fixed length chord of line,the orthogonal least square iterative fitting method is used to determine the plane characteristic parameters of the railway line.By comparing and analyzing the design data of Yinxi Passenger Dedicated Line,the obtained characteristic parameters of line curve are basically consistent with the design values.(4)The detection algorithm of railway structure gauge and assessment algorithm of tunnel state based on point cloud data.Through realizing continuous point cloud slicing based on mid-line data,a single point cloud slice is projected to the coordinate plane to realize the cross-section extraction and measurement.Taking the rail top surface and the mid-line as benchmark,the structure gauge model of high-speed railway is constructed,and the improved ray method is used to realize the detection of railway structure gauge.Based on the tunnel cross-section data,compared with the tunnel design cross-section,the overbreak and underbreak and deformation of tunnel are analyzed,and the tunnel state assessment is realized.At the same time,the experiments of detecting railway structure gauge and tunnel state assessment are completed in the experimental area of Yinxi Passenger Dedicated Line.