Research On Technologies Of Battlefield Environment Modeling And Situation Generation

Information advantage has been considered as a crucial element to enhance battle effectiveness. There are lots of traditionary battlefield environment data. They are from different sources and have diverse formats. These environment data are separate and hard to meet the requirement of all-around real-time battlefield environment awareness in the modern war. So it is necessary to process these environment datas, extract basic spatial information, then integrate geographical spatial information and spatial intelligence together to provide a unitive battlefield situation in support of combat decision-making. With the support of national administration's research project, this dissertation studys three aspects of digital battlefield environment supporting technology: battlefield geographical environment digitization, battlefield geographical environment visualization and battlefield situation visualization. The aim of this study is to break through the key technologies, design and realize a battlefield environment modeling and situation generation prototype system– BEMSG.The main contents and accomplishments are as follows:The vectorization of scanned maps is a difficult process due to aliasing and false colors induced by the scanning process and due to closely spaced and intersecting/overlapping features inherent to the maps. In this dissertation, an object-oriented approach is introduced into scanned map segmentation. The procedure is described as follows. First, linear elements and area elements are separated. Then they are partitioned into image objects which are basic cells to classify map features, not single pixels. And a set of features combining color, shape and topology are extracted from each object. Based on the features, a classification criterion is employed to perform the map segmentation. The proposed method overcomes aliasing and false colors induced by the scanning process. The results seem coherent, with none of the "salt and pepper" noise.A kind of DEM constructing method based on spatial index is proposed. First, quad-tree index is created to manage triangles, so as to reduce searching area. Then, the topology of triangles is established. According to it, a gradual strategy is used to locate the goal triangle and ascertain influenced area of constrainded boundary quickly. The experiment results show that the method can effectively improve the speed of constructing TIN from contours. Finally, the regular structure of grid DEM is used to create spatial index directly, which can index all grid points in each triangle rapidly. The experiment results show that the spatial index can accelerate the interpolation of grid DEM from TIN remarkably.A kind of vector data displaying algorithm based on view-dependent projective texture-mapping is proposed. First, depending on the scene view, a perspective projection is created, which can match the currently terrain visible range well. Then it is used to generate the texture on-the-fly and calculate the texture coordinates in GPU. Quality superior to standard texture mapping is achieved by using the view-dependent perspective projection, which can improve the availability ratio of texture pixels. In addition, since the algorithm is independent of the underlying terrain geometry, it is suited to work with terrain LOD and image pyramid algorithms.A kind of military symbols rendering algorithm based on displacement mapping is proposed. First, terrain is smoothed using the programmable fragment processor on GPU, to wipe off local details and reserve the main hypsography. The result is rendered to a displacement texture on the fly. Then, 2D outlines of irregular military symbols are generated, used to trim NURBS surfaces to create military symbol grids. Finally, according to the displacement texture, all vertices of the military symbol grids are displaced using the programmable vertex processor on GPU. The algorithm allows high-quality overlay of military symbols on virtual landscapes, and is GPU-based, can meet the real-time requirement of interactive edit and dynamic plotting.A prototype system– BEMSG is designed and implemented. The general framework, software subsystems of the system are constructed. The application in a manoeuvre validates the feasibility, effectiveness and correctness of the proposed theories, algorithms and the system constructed in the dissertation.