Building Facade Modeling Based On 3D Laser Scanning Technology

As an indispensable part of digital city,buildings have become an important research object of urban 3d modeling.Three-dimensional laser scanning technology provides a new data acquisition technology with high efficiency and high precision for the acquisition of spatial information.With the rapid development of three-dimensional point cloud modeling technology,it has become a research hotspot in the fields of digital city,reverse engineering,and conservation of ancient buildings.Although the process of building point cloud acquisition and data processing by 3d laser scanner is becoming more and more mature there are still many technical problems to be solved.In addition to the required target point cloud,a large amount of original point cloud data also contains many non-target point cloud data,a large number of data calculation and too much manual error will cause precision loss,which requires further process ing to accurately extract the building feature information and improve the modeling accuracy.In this paper,HS450 ground 3d laser scanner was used to obtain 3d laser point cloud data before and after the campus reconstruction,and the details of data acq uisition operation and some matters needing attention in the implementation process were analyzed in detail.Method summary and experimental operation are carried out for the preprocessing process of point cloud data registration,noise reduction,simplification and segmentation.The feature extraction of building facade is studied and analyzed.the specific algorithm strategy and process for the wall and window feature extraction were proposed and implemented.Experimental studies have shown that,Although the algorithm strategy of wall contour extraction can extract the simple building facade wall contour,the effect and efficiency is not as good as the plane extraction function of professional software,and the algorithm process needs to be improved.Window extraction results can better show the overall contour effect of the window,The extraction method of Windows with different structures can be further optimized.The process of extracting building facade features is analyzed and summarized through experimental operationThe surface reconstruction method and parametric method are also studied in this paper.Geomagic software was used to model the point cloud data of the front facade of the teaching building with the surface reconstruction method.Although the effect of local detail model was realistic,the modeling could not be completed until the polygon stage at most.Then parameterized modeling and effect analysis of point cloud feature extraction based on 3D Max software and Sketchup software were performed respectively,Two different modeling processes of 3D Max software are emphatically analyzed.The corresponding solutions to the problems encountered in the process of modeling are given and good results are achieved.Finally,the applicability of two different modeling techniques,surface reconstruction method and parametric method,is compared and analyzed.The modeling of large buildings is more suitable for parametric method of feature line extraction.