| The Oblique photography three-dimensional model has the characteristics of fast data acquisition,short modeling period,rich bearing information and 3D spatial analysis,and has become a key application technology in today and in the future.The theory and technology of the Oblique photography three-dimensional model has been greatly developed in recent years and has been widely used in many industry fields.However,there are still some technical difficulties in model optimization,model data organization and model depth analysis application.First,due to the cavity phenomena caused by the quality of image data acquisition,it seriously affects the integrity of the 3D model.Not only is the visual effect of the model poor,but also it is difficult to analyze the data association and use of the model cavity.The second is that the feature of the Oblique photography three-dimensional model and the ground at the data structure level is a whole,which is difficult to factorize and brings difficulties for specific applications.The main research contents of the thesis are as follows:(1)Research on cavity identification and patching algorithm for the Oblique photography three-dimensional model.On the basis of extracting the boundary of the suspected cavity area,an algorithm for automatic identification of defect cavities and detail optimization of geometric features is studied.The algorithm automatically detects the extracted context and contour curves of suspected voids and determines that the suspected void belongs to the model itself.Shape or structural features,or defective voids that need to be repaired,and then use the feature points around the cavity area to generate feature lines to construct the base surface of the cavity area,and preliminary segmentation of the base surface by dynamic programming method to obtain a rough segmentation result,and finally the triangular mesh is refined and adjusted from the boundary of the cavity to the center to improve the geometric properties of the mesh.The experimental results show that the method can effectively restore the geometric features of the model void region.(2)The Oblique photography three-dimensional model data structure design.Based on the analysis of the existing 3D GIS platform data structure solution,combined with the application requirements to analyze the design principles of 3D data structure,the extended definition is based on the existing 3D data structure,and the design conforms to 3D data efficient browsing,data editing and data.Analyze the data structure,realize the oblique photography 3D model and manual modeling model,3D laser scanner point cloud data,vector data,plane 2D data and online data service loaded into the same scene for browsing.(3)Based on Cesium 3D GIS application system development.Design and develop a 3D GIS application platform based on Cesium framework,which encapsulates multiple industry common operation modules for tilt photography 3D model.The goal is to solve the problem of repeated coding of the same demand by multiple platforms,reduce code coupling,enhance system compatibility,and reduce the purpose of development cost is to provide services for the oblique photography 3D model in the fields of intelligent transportation,intelligent house management,pipeline planning,and environmental monitoring. |
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