Monitoring Method Of Prefabricated Building Construction Process Based On Point Cloud Model Feature Extraction

China’s prefabricated buildings have entered a period of rapid development.Due to factors such as immaturity of technology and the break of the information chain between various disciplines,prefabricated construction projects generally suffer from construction schedule delays and quality problems caused by construction errors.Effective monitoring of the construction process of a construction project is one of the key factors for project success.However,the current construction site data collection mainly relies on manual methods,which are time-consuming and labor-intensive,and the information is not comprehensive.The emergence of 3D laser scanning technology provides a new way to collect construction site data.In order to better manage the prefabricated building construction process,this paper proposes a prefabricated building construction process monitoring method based on point cloud model feature extraction,the main contents of the article are as follows:First,the paper introduces the data indicators and existing acquisition methods of prefabricated building construction quality and progress monitoring,and the basic theory of3 D laser scanning.Then uses a 3D laser scanner to complete field data collection,and obtains point cloud data of prefabricated building construction sites.Second,the point cloud data is preprocessed,and the prefabricated component segmentation and geometric feature measurement are completed based on the PCL platform.Aiming at the problem of noisy points and large amount of data in the original point cloud data,the preprocessing is completed through the steps of constructing topological relations,thinning,and denoising.According to the spatial position relationship and geometric characteristics of the prefabricated frame structure,design the segmentation algorithm process to realize the segmentation of two typical prefabricated components of column and beam from the overall point cloud.By processing the point cloud data of single columns and beam components,the geometric dimensions of prefabricated columns and beam components are measured.Third,monitor the construction quality of prefabricated buildings.Determine the design elevation of the site through 3D laser scanning technology.Simulate the assembly construction of prefabricated components to realize quick inspection of whether the steel bars are bent or deviated.Detect the verticality of the wall by calculating the angle between the normal vector of the fitted plane and the unit vector in the vertical direction.Use point cloud slices to extract the central axis of the column to detect the verticality of the column.The flatness of the board surface is expressed by the median error from each point to the fitting plane.Fourth,monitor the construction progress of prefabricated buildings.Use Revit to create a BIM design model of a prefabricated building,complete the positioning and registration of the point cloud model and the BIM design model through the rotation matrix transformation and link the model coordinate system,and compare the point cloud model and the BIM planning model to achieve visual monitoring of the construction progress.Fifth,on the basis of the above research,the prefabricated building construction process monitoring system based on point cloud model feature extraction is designed,and a monitoring system database is established to prepare for software development.The overall system architecture includes four layers,and the functional application layer includes three main functional modules,through which the monitoring of the prefabricated building construction process is realized.