Research On 3D Modeling And Rendering Of Electromagnetic Environment In Virtual Battlefield

The acceleration of military information evolution, the increasingly complex battlefield electromagnetic environment, and unprecedented intensified struggle in electromagnetic space have a profound impact on military activities. In the invisible struggle front of electromagnetic space, the description of electromagnetic environment is the key factor of restricting commanders to implement command accurately and efficiently. Scientific, accurate and intuitive description of the electromagnetic environment not only helps commanders to determine the battlefield electromagnetic situation accurately and scientifically, and to deploy and prepare the warfare electronic forces reasonably, but also is important for joint operation commanders to grasp the battlefield situation accurately. Therefore, nowdays the need of visual and accurate representation of electromagnetic environment in virtual battlefield is urgent.This thesis focuses on the research of 3D modeling and rendering of electromagnetic environment in virtual battlefield. The data modeling and multi-isosurface mesh modeling method of electromagnetic environment is studied; in order to enhance the representation, the multi-isosurface blend rendering and direct volume rendering method is studied; in order to improve the rendering performance, the acceleration technology based on graphics hardware and the algorithms of volume data multi-resolution construction and model mesh multi-resolution dynamic simplification are studied. Some corresponding theories and application problems are analyzed and discussed thoroughly and a number of innovative research results are made. In detail, the main contributions of this thesis are described as follows:In order to model the data of electromagnetic environment in virtual battlefield, a Spherical Regular Grids volume data structure is proposed and a common framework for hardware-accelerated electromagnetic environment computing is presented. Based on the radio propagation model, the Spherical Regular Grids volume data structure is proposed to construct uniform numeric description of the electromagnetic environment volume data in virtual battlefield. In order to speed up the construction of 3D electromagnetic environment volume data, the method of hardware-accelerated electromagnetic environment calculation is designed through abstracting the input, output and computing kernel of electromagnetic environment data model. And the common framework for hardware-accelerated electromagnetic environment computing in virtual battlefield is built.A method of hardware-accelerated electromagnetic environment multi-isosurface modeling and dynamic simplification is proposed. In order to represent more electromagnetic information, the algorithm of hardware-accelerated multi-isosurface extraction is proposed. And the technique of simultaneous extraction multi-layer of isosurface at one time is achieved, which speeds up the multi-isosurface modeling. The view-dependent and volume preserved electromagnetic environment isosurface multi-resolution dynamic simplification algorithm is presented. This algorithm considers the area-weighted and mesh salient. Therefore, the simplification algorithm not only maintains the isosurface geometry characteristic, but also maintains the regional characteristic of the mesh. The triangle collapse woods is built using top-down approach, and the triangle collapse state subset is designed to implement the dynamic selection multi-resolution mesh at different region based on view-point.Two multi-isosurface semi-transparent rendering algorithms are proposed. In order to fast roam and wide angle view the multi-isosurface, pseudo-sorting algorithm is proposed to achieve the multi-isosurface in approximate order quickly, and avoids the sort operation on a large number of faces. In order to improve multi-isosurface rendering quality, the improved multi-pass Depth Peeling algorithm based on bucket sort and slicemap is proposed to solve the problems of multi-isosurface fragment uneven distribution. And the complex isosurface rendering ability is improved.A hardware-accelerated and free roaming supported electromagnetic environment direct volume rendering method based on hybrid octree is proposed. For the large-scale electromagnetic environment Spherical Regular Grids volume data, the hybrid octree divided structure is proposed to solve the problem of dividing the volume data which has variant dimension size. And the multi-resolution ray casting spherical direct volume rendering is proposed. The virual octree structure is designed to construct the tight volume rendering bounding box, so the volume rendering is accelerated. In order to solve the problem that the traditional hardware-accelerated direct volume rendering algorithm can not correctly handle the issue of view frustum crossing the bounding box, the correctional method of the view frustum cull is proposed. And the free roaming of volume rendering is realized.For the Cylindrical Regular Grids volume data of a single electromagnetic device, the ray casting cylindrical direct volume rendering algorithm is proposed. And the visualization of the Cylindrical Regular Grids volume data is achieved.A prototype system of electromagnetic environment 3D modeling and rendering in virtual battlefield named EMSimVis is designed and implemented, which gives a experimental support to electromagnetic environment modeling and rendering in virtual battlefield. And some parts of this system are applied in related projects.