Research On Target Location And Fusion Of Virtuality And Reality In Virtual Geographic Environment

With the in-depth development of GIS, virtual reality, and augmented reality, virtual geographic environment has gradually become important research direction in the GIS. Video, as a common medium, has a strong sense of reality, real-time, meanwhile, and fidelity in terms of geographical spatial expression, so can be beneficial supplement of geographic spatial information. Combining with abstract expression of virtual geographic environment and the concrete expression of video, integrating video images and geographic data, and seamless dynamic fusion, provides not only a new solution for spatial position of monitor target, but also immersive expression. Research and results are as follows:(1) This paper expounds research status and develop course of virtual geographical environment, summarizes research status about video monitoring technology and augmented reality applications in the field of virtual geographic environment, and shows practical application and development prospects of geographic visualization methods which take vedio image as the carrier.(2) Introduce element type, modeling method and technology in virtual geographic environment. Taking advantage of the advantages of osgEarth and OpenSceneGraph, we build virtual geographical environment, based on quadtree data structure, paging database scheduling policy and scene graph data organization and management.(3) According to the consistency of the OpenGL persective imaging mechanism and photogrammetry theory, we propose a geographical scene target position estimation method which is based on virtual imaging simulation of three-dimensional scene and video image. In the condition of knowning camera photogrammetry exterior and interior parameters, we firstly create virtual camera model for simulating actual imaging process in three-dimensional scene, then the screen coordinates are derived based on the target pixel coordinates in the single frame video image, and later tramsformed into world coordinate system according to the inverse process of virtual imaging. Finally, We use 3D laser scanner and digital camera to obtain 3D point cloud data and digital images to simulating the actual video monitoring system composed of high precision digital holder and digital camera.(4) For the problem of virtual expression of the three-dimensional GIS, based on the target positon research, we have achieved seamless integration of the video image and virtual virtual scene by the perspective matching methods in the conditons that internal and external orientation parameters have been known.(5) Based on forest landscape visualization system VisForest, we expanded the three-dimensional virtual scene imaging, target positioning and integration module between virtual scene and the video frame, etc. Through the experiment, we proves the method is feasible.