Research On Construction Progress Monitoring Method Based On Voxel Model

Project management has an important role in supervising and guiding the life cycle of the project,which is directly related to the efficiency and credibility of the enterprise.Engineering construction schedule management accompanies the whole process from project initiation to project completion,and is an important guarantee that construction tasks are carried out in an orderly manner and completed successfully according to the construction schedule.In recent decades,large-scale projects and mega-projects have been built in China and even all over the world.The complex environment and cumbersome process at the construction site of large-scale projects have invariably increased the workload and difficulty of construction progress management,and the traditional means of monitoring construction progress by manual on-site is inefficient,blind,task-intensive and costly,which is far from meeting the requirements of modern construction.It is significant to explore a time-saving,labor-saving and efficient construction progress monitoring method.In terms of data collection,compared with manual information collection,UAV tilt photography can quickly collect image data from construction sites,which has the advantages of low cost,high efficiency and simple operation.As for 3D modeling,compared with BIM models,point cloud models,4D products and other kinds,3D reconstruction and change monitoring of buildings based on voxel models have the advantages of rich attribute information,internal visualization and good visual effects.To address the above issues,this paper takes a building at a construction site in Daxing District,Beijing as the monitoring object,adopts UAV tilt photogrammetry for construction data collection and voxel model for progress monitoring.The main research contents are as follows:(1)Three dimensional change monitoring.According to the point cloud generated by the inclined image,the two-phase three-dimensional voxel model of the target building is established by using the point cloud voxel conversion algorithm,and the voxel difference model is obtained by comparing the two-phase voxel models,including three types of increase,decrease and unchanged,which is the result of the three-dimensional change of the building within the planned construction period;(2)Two dimensional change monitoring.The five views refer to the orthographic projections of the building in five orientations: front,back,left,right and top.Based on the two-phase voxel model,the real color information is given separately,and then the face pieces of each orientation in the voxel model are projected orthogonally separately to generate two phases of five views.Image segmentation and image classification are performed on the five views,and the comparison yields the five-view difference map,which is the color change result of the five exterior surfaces of the building during the planned construction period.Finally,according to the construction schedule,actual construction schedule,voxel difference model and five view difference diagram,the construction schedule is analyzed to guide the construction management.The experimental results show that the total construction of Building 5 is completed by 85% in four months,and the progress is delayed by 15%.The experiments show that the change monitoring method based on voxel model and five views in this paper can view the construction progress in both 3D and 2D perspectives,which can present the construction progress better and provide services for construction progress management.