Research And Implementation Of 3D Ocean Virtualization Based On Electronic Chart

With the rapid development of computer science and technology, Computer graphics and virtual reality technology have a wide range of applications in all spheres of life, entertainment, medical, industrial and military fields. The land, sea, air, space, network are defined as five-in-one in the battlefield situation of electronic information system. Nowadays the requirements of the five-in-one are an important part of military combat readiness. The territory of China contains a large area of ocean, but the technical resources are relatively scarce. Therefore, it is important to restore the realistic ocean geographic environment and obtain the information of ocean battlefield situation rapidly and accurately. Also it has important significance for the development of virtual ocean and military electronic information system.In this thesis, The massive 3D ocean is modeled by using data and methods from electronic chart and geographic information system. The technology of virtual reality is used to turn the abstract and indistinct ocean battlefield situation information into intuitionistic 3D graphic information. Combined with COSTAS arms trade projects, the 3D ocean plug-ins are integrated in the 3D geographic information system platform. It is also efficient for secondary development.(1) The data of electronic chart based on S-57 is extracted and managed to model the digital terrain model. A method of demand interpolation based on neighbor searching and a method of GPU parallel processing are proposed to model the sea terrain fast and accurately. A method of image space is put forward which is combined with frame buffer object and render to texture to render the undersea scene.(2) Combined with GPU parallel processing, the fast Fourier transform based on spectrum analysis is used to model the ocean surface. The Phong illumination model is used to render reflect, refract, Fresnel effect. The technology of texture overlaying and bump mapping are used to achieve the effect of foam and fold.(3) The OSG frame is introduced and the geographic information system platform based on OSG is used to integrate the 3D ocean plug-in. Problems are solved in this chapter including LOD, linking and pathing, land-sea connecting, ship wakes. The results are showed out and meet the demand of real-time and reality.(4) This thesis analysis and summarize the problems and deficiencies in the 3D ocean, and propose improvements and prospects for future work.