Research On Building Flatness Detection Based On 3D Laser Scanning And BIM Technology

In recent years,the state vigorously industrialization,information technology can assign construction in the basic realization of socialist modernization in China,to continue making the "China construction" is the core competitiveness of the world’s leading standard,the building process of industrialization to promote to a higher level.Engineering quality inspection plays an important role in construction.As an important part of the quality acceptance of construction engineering,wall roughness has been widely concerned about the update of its detection technology.Traditional flatness measurement methods based on ruler,plug gauge and total station have limitations in efficiency and accuracy,which are difficult to meet the current detection of building wall quality.Based on this,this paper integrates the advantages of 3D laser scanning technology and BIM technology to carry out research on the detection scheme of building wall smoothness.In this paper,the working principle of 3D laser scanning system,the classification of the equipment carried on the thorough analysis,scanning precision,summed up the characteristics of BIM technology,summarizes the analysis software Geomagic-Qualify.A new scheme for processing initial point cloud data is designed to meet the requirement of cloud extraction of effective points.Based on theoretical and practical analysis,the advantages of 3D laser scanning combined with BIM in flatness measurement are obtained,and the scheme is summarized.The main research contents of this paper include:Firstly,the point cloud data obtained by 3D laser scanning is extracted by RANSAC algorithm,and the extracted point cloud is processed by one-sided R-radius density algorithm.Based on the principle and experiment,this paper analyzes the shortcoming of R-radius density in processing RANSAC algorithm to extract one-sided building point cloud.On this basis,it uses the characteristics of RANSAC algorithm to extract point cloud facets,and puts forward the point-surface relationship algorithm to optimize the shortcoming of RANSAC algorithm to extract one-sided building point cloud.Through example analysis,the noise efficiency and effect of R radius density and point-surface relation in processing the extension surface of extraction surface in RANSAC algorithm are compared,which shows that RANSAC algorithm combined with point-surface relation method can satisfy the accurate extraction of building facade point cloud data.Secondly,the traditional flatness detection methods are analyzed,and the advantages and disadvantages of the traditional flatness measurement are summarized.By comparing the three methods of applying effective point cloud data extraction to wall flatness detection,it is theoretically concluded that the system error of point cloud-BIM scheme is the smallest,which is conducive to the index analysis of flatness.Combined with examples,the optimal registration methods of cloud of different measurement stations are explored,and the comparison shows that the feature-IPC registration has the characteristics of high registration accuracy,minimum error and stable error value.By analyzing the registration scheme of point cloud data and BIM data through an example,it is concluded that RPS-best fitting registration method has the best effect.Six flatness measurement methods were used to measure the flatness of 30 points respectively.It was concluded that 3D laser scanning combined with BIM had the most advantages in flatness measurement.In addition,the application of 3D laser scanning combined with BIM technology in flatness measurement is summarized.Finally,combined with the plastering project of the south facade of "Guang Xingli" in Qingdao,the application research of point cloud-BIM flatness measurement was carried out to verify the feasibility of the research content in the engineering application.Under the background that digital technology is constantly infiltrating into the engineering field,3D laser combined with BIM technology is applied to the engineering to effectively give full play to the advantages of the two and improve the efficiency and precision of engineering quality detection.This study provides ideas for the application of 3D laser scanning combined with BIM technology in other fields of construction engineering,and it is of great significance to promote the integration of various digital technologies into construction engineering.