Study On Key Technology Of Visual Simulation For Mountainous Expressway Driver-Vehicle-Road System

Through the computer simulation of reality road line type, road surface condition and traffic environment on the visual simulation platform, the computer simulation aimed at the research of traffic using the virtual reality technology. The virtual reality technology provides the high-tech research means, which is significant on the road traffic in practice. Because the safety ensuring system of mountainous expressway is faultiness, there is a big hidden danger. Visual simulation for mountainous expressway Driver-Vehicle-Road system is the visual technology of improving the road traffic safety, which is the application of virtual reality in the problerm of mountainous expressway safety. However, the veracity of virtual test affects the veracity of safety detection and the validity of safety ensuring engineering. Therefore, it is significant to impove the real-time, validity and realisticness of visual simulation for mountainous expressway Driver-Vehicle-Road system in the process of the mountainous expressway safety assessment.Based on proving that the virtual reality technology is feasible in the assessment research of drivers' road safety, this dissertation researches on the optimizational technologies of virtual reality system, 3D terrain generation technique with GIS and the lifelike scenery building technology, also applies this technologies to the mountainous expressway safety research.(1) This dissertation put forward that applies the virtual reality to the assessment of mountainous expressway safety. This dissertation analyses the existing issues about speed, terrain generation and realistic rendering, when evaluates the mountainous expressway safety using Driver-Vehicle-Road visual simulation system. This dissertation concludes that it is feasible to research the Driver-Vehicle-Road safety problem using virtual reality.(2) This dissertation studies on the the optimizational technologies of visual simulation system for mountainous expressway Driver-Vehicle-Road system. Through the research of LOD technology, this dissertation studies on the LOD technology in the process of mountainous expressway model rendering, selects the method of selecting LOD, and studies on the application of LOD technology in the mountainous expressway simulation model. Through the analyses of realtime cull order and realtime draw order, the analyses of texture mapping theory and algorithms, the method analyses of reducing the polygon count, and the analyses of bounding volume theory in the Multigen Creator/Vega system, this dissertation researches on the application of optimizational technologies in mountainous expressway virtual model, which include the method of adjusting the openflight data hierarchy structure, texture mapping technology and bounding volume technology, and so on.(3) This dissertation studies on 3D terrain generation technique of visual simulation system for mountainous expressway Driver-Vehicle-Road system.Through the research on the conversion method between GIS original terrain data and data format which are needed in modeling, this dissertation studies on 3D terrain generation system of mountainous expressway with GIS based on the analyses of DEM and 3D terrain generation method. In addition, through the research on terrain transformation algorithm, this dissertation selects the transformation algorithm of mountainous expressway vitual terrain. This dissertation also applies mountainous expressway terrain model generation system to terrain generation of Xihan expressway.(4) This dissertation studies on lifelike scenery building technology of visual simulation system for mountainous expressway Driver-Vehicle-Road system.Based on the theory of illumination model and shading mode, this dissertation research on the application of illumination technology in mountainous expressway simulation system.Through the analyses of aliasing phenomena realtime navigation system with MultiGen Creator/Vega, this dissertation studies on antialising technology to enhance the reality of the scene.Through the research of non-photorealistic rending technology, this dissertation studies on the application of caricature technology in visual simulation system for mountainous expressway. Based on fuzzy comprehensive evaluation method, this dissertation also studies on the fidelity evaluation method of visual expressway.(5) This dissertation applies the optimizational technologies, 3D terrain generation system with GIS and lifelike scenery building technology to the mountainous expressway modeling and scenes-driving. Through the virtual test, this dissertation studies on the assessment of optimizing effect and the assessment of scene fidelity. This dissertation also studies on the application of Xihan expressway simulation system in the designing of safety ensuring engineering facilities.In general, the key points of innovation in this dissertation mainly rest in the following aspects:(1) Through studying on the model optimizing technology of large-scale virtual scene, this dissertation applies LOD technology, the method of adjusting openflight data hierarchy structure, texture mapping technology and bounding volume technology to the mountainous expressway simulation system. Therefore, the polygon count can be reduced and the operating speed can be enhanced. (2) This dissertation develops 3D terrain generation system of mountainous expressway with GIS database. Through the research on the conversion method of GIS original terrain data and terrain transformation algorithm, this dissertation also applies the 3D terrain generation system to the large-scale terrain generation of mountainous expressway.(3) This dissertation applies the illumination technology, antialising technology and caricature technology to visual reality system for mountainous expressway, and validates the fidelity of mountainous expressway simulation system using the fuzzy comprehensive evaluation.