Research On Key Technologies Of Automatic 3D Measurement Of High Speed Railway Hub Based On Line Laser Scanning

Line laser 3D measurement is an optical non-contact 3D measurement technology.It can achieve fast three-dimensional scanning of objects,and has the advantages of high speed,high precision,and good stability.With the rapid development of laser,microelectromechanical and semiconductor,it is widely used in many fields such as reverse engineering,equipment manufacturing,aerospace,medical and health,cultural relics,archaeology and public security criminal investigation.However,due to the limited measurement range of line laser sensors,it is often difficult to obtain complete measurement data for single-line laser sensors when detecting high-speed rails.Multiple line laser sensors are required to cooperate with high-precision rotary tables.In order to realize the correct fusion of the three-dimensional data collected by the multiple sensors in the line laser measurement system at different angles of rotation of the turntable,and to obtain the complete three-dimensional data of the high-speed railway hub,this paper research three-dimensional line laser measurement technology,camera calibration technology,axis calibration technology,and digital images processing technology,designing a line laser measurement system to complete the three-dimensional measurement of the high-speed rail hub.The main tasks completed in this paper are:(1)The principle of visual three-dimensional measurement was studied,such as the imaging model of the camera and the three-dimensional measurement principle of the line structure light.The calibration technology of the shift-axis lens camera and the laser plane calibration technology were studied.And the camera calibration,laser plane calibration,coordinate system registration has been completed.(2)Principle of the axis calibration,fitting model and solving method of space geometry such as space line,space circle and plane,have been studied systematically.According to the actual measurement needs,the relevant calibration algorithm was designed to complete the calibration of the rotation axis space of the measurement system.(3)The calibration principle of the line laser sensor in the measurement system and the camera space pose estimation method have been studied systematically.A relative calibration algorithm was designed and implemented to complete the spatial calibration of the line laser sensor in the measurement system.(4)Digital image processing techniques such as grayscale change,spatial filtering,morphological processing and feature extraction have been researched systematically.Designed and implemented an encoding and decoding algorithm for coded landmarks in high-noise scenes to complete decoding of blurred image-encoded landmarks.