Research On Key Techniques Of Oblique Photogrammetry Based On Wide-angle Panoramic Camera

3D browsing can express 3D objects objectively,truly and intuitively,and becomes one of the research hotspots of "digital city" and "wisdom city".It can browse in any direction of all 360 degrees,and have realistic effect and immersive interacting,so that it has been widely used in city planning,intelligent navigation,VR(Virtual Reality).There are two ways of 3D browsing:3D modeling and 3D panoramic views.At present,3D city modeling mainly use oblique photogrammetry,which has true and objective model,but need to collect large amounts of data,and the processing time is long,cannot display real-time 3D scene.Panoramic view can do fast stitching and real-time 3D browsing,however,it lacks image position and attitude information,that makes it hard to be measured.Compared with the standard camera,wide-angle camera,which has a larger viewing angle,can obtain its more abundant information,save the camera cost,and at the same time meet requirements of panoramic image stitching.So it is widely used in panoramic stitching and browsing.But wide-angle camera has great image distortion,which will lead to deformation or distortion of the object in the obtained image,and have impact on the result of image matching and the precision of image pixels,so it cannot be directly applied in 3D scene modeling.If the image obtained from wide-angle lens camera can be applied to aerial panorama stitching,and also meet the requirements of oblique photogrammetry,refine3D modeling,it can reduce operating costs,integrate the air and panoramic oblique photogrammetry,and has good application prospects.In order to achieve a goal that the wide-angle camera can be used for three-dimensional panoramic views and also can be applied to oblique photogrammetry 3D modeling,this paper takes wide-angle image,which is acquired by six lens small ants moving camera equipped on the UAV,as the research object,according to the large geometric distortion of wide-angle image and complex zone modeling scene,proposed two ideas of the geometric correction of wide angle camera,and projection transformation based on panoramic image,to eliminate or weaken the effect of distortion of image matching to the subsequent image matching,realize 3D modeling with high precision.Because the wide-angle images and panoramic images both have the large distortion,they cannot be directly applied to the texture map,at the same time,the complexity and particularity of 3D scene claim on the choice of the texture,so the establishment of reasonable selection mechanism of texture and processing model are in need,which will construct more realistic3D model.The main research contents and results of this paper are as follows:(1)Study on imaging model of the wide-angle camera geometric correction model.Through researching the model of wide-angle lens imaging,this paper analyzes distortion factor of camera,realizes image distortion correction based on distortion model,provides high quality data sources for the image matching and 3D reconstruction of the latter part.(2)Research on Imaging model and projection model of panorama image.Based on the study of panorama imaging model,this paper establish projective transformation model,the panoramic image is projected as orthographic image,provide quality assurance for the three-dimensional reconstruction of the latter step,and at the same time provide a way of thinking and technology for the tilt photogrammetric processing based on wide angle panoramic images.(3)This paper studies the texture mapping method in 3D reconstruction.To solve the problem 3D model texture mapping,this paper design the reasonable texture mechanism and mapping strategy,realize 3D modeling with high precision.(4)Verify the accuracy of geometrical correction of wide-angle camera image and the accuracy of oblique photogrammetry based on panoramic image projection.Analyze the accuracy of two kinds of methods,and do the comparative evaluation.The result shows that the two methods can both realize three-dimensional modeling,and its precision can meet the requirements of general project.