Calculation Method Of Mean Texture Depth For Asphalt Pavement Based On 3D Point Cloud

The skid-resistance performance of asphalt pavement has a significant impact on driving safety.The mean texture depth(MTD)of pavement is a key indicator for judging the skid-resistance performance of pavement.The traditional point laser measurement method only measures the texture depth of the wheel track,and does not truly reflect the texture depth state of the entire road surface.This paper proposes a 3D point cloud texture depth calculation method,which realizes asphalt pavement texture extraction,3D reconstruction and MTD calculation,and carries out experimental verification on the actual road.The main research contents are as follows:(1)The advantages and disadvantages of different 3D measurements are analyzed.The principle of 3D measurement of line structure light scanning is studied,and the characteristics of 3D measurement technology of structured light are summarized.The 3D data of asphalt pavement was collected by line scan 3D system.The composition of pavement data was analyzed.For the 3D point cloud data characteristics of pavement,the profile data processing method based on wavelet transform was proposed to realize the acquisition of 3D point cloud of pavement macrotexture.(2)By acquiring the full-surface 3D point cloud data of the pavement and reconstructing the 3D pavement based on the 3D point cloud,the mean texture depth of the whole road can be measured.The 3D macrotexture model of asphalt pavement was reconstructed by point-by-point insertion triangle mesh construction method.The topological relationship of macrotexture data was analyzed.A method for separating strip macrotexture data based on 3D macrotexture model was proposed.The texture depth calculation model of the planar texture point cloud is established,and the calculation of the planar mean texture depth is realized.(3)The influence of the actual driving measurement environment on the texture depth measurement is analyzed.The verification experiments of different speeds and texture types are carried out.The experiment shows that the algorithm repeatability is above 91%.Compared with the SMTD of point laser measurement,the MTD correlation coefficient is more than 90%,with practical engineering application value.Finally,the factors of MTD measurement error are analyzed,and an improvement scheme is given from the aspect of setting the coverage point cloud percentage parameter to improve the accuracy of measurement.This thesis studies the calculation method of mean texture depth based on 3D point cloud.The calculation results in this paper can objectively evaluate the safety condition of road surface,and can simultaneously satisfy the high efficiency、high precision and full width measurement requirements,and better solve the one-sided problem of point laser measurement method caused by point to face measurement.This method has more practical value and good application prospects for asphalt pavement safety assessment and maintenance decision-making.