Three-dimensional Fine Modeling Of Chemical Park Based On UAV Oblique Photography

Since the 13th five year plan,chinese chemical industry park had entered a new stage of development with improved quality and efficiency.However,due to its unreasonable planning,safety and environmental protection accidents occurred from time to time,it is necessary to further standardize the construction and strengthen the integrated management of the park.The three-dimensional real model can directly reflect the spatial location and surface texture of buildings,it can be well applied in the integrated management of chemical industry park.Because there are many kinds of buildings in the chemical industry park,and their shapes are different,especially there are many cylindrical storage tank buildings,so it is difficult to build the three-dimensional model of the chemical industry park.The traditional three-dimensional modeling method needs a lot of human-computer interaction,high production cost and long time.But the combination of industrial UAV and tilt photography technology can be used for large-area,fast and efficient three-dimensional solid modeling of chemical industry park..However,the flying posture of the UAV and the angle of the camera to collect data,it will cause the geometric distortion of some ground buildings and the unclear regional texture.In response to the problem of UAV tilting photogrammetry technology,the three-dimensional model was refined.It included the repair of common problems and fine processing of texture,and the accuracy of three-dimensional model was evaluated and analyzed.The main contents of this paper are as follows:(1)The UAV tilt photogrammetry system was built to collect the tilt image data of the target area.The specific operations include survey of survey area,layout and measurement of image control points,selection of UAV and camera,route planning,flight operation,data sorting and inspection,etc.By controlling the details of each step,the quality of oblique image and the accuracy of image control points can be improved as much as possible.(2)A three-dimensional real model was built,and the accuracy of the model was analyzed.After preprocessing the data,we used contextcapture software to import tilt image photos,POS data and image control point data,automatically calculated the camera position and camera parameters of each photo,and then obtained ultra-high density point clouds through dense matching,and then connected the point clouds to build a triangular grid to form a highresolution digital surface model.Finally the texture was extracted from the image and automatically mapped to the model to form a three-dimensional real model.Finally,the accuracy analysis of the model was reflected in two aspects: the first aspect was to analyze and evaluate the three-dimensional accuracy of the five module areas.And the second aspect was to use the image control points as the verification points to analyze and evaluate the accuracy of the three-dimensional model.(3)The Model was refined.Aiming at the built three-dimensional real scene model,the problems such as the water surface cavity,suspended solids,structural distortion,serious hollowing out and other problems were repaired.And a method of making full use of oblique images and on-site photos taken in the field to refine the texture of the building was proposed.The results showed that this paper solved the problems of model distortion and unclear regional texture.And the structure of the repaired three-dimensional model was fine and the texture is clear,and the root mean square error of the plane and the elevation meet the requirements of grade ? of the product specification for three-dimensional geographic information model data.The three-dimensional model was applied to the integrated management of chemical industry park to provide more accurate reference,and this will be of great significance to the fire safety of the park.