Research On Dynamic Virtual Environment Modeling And Rendering Based Catadioptric Panorama

Modeling and rendering of dynamic virtual environment is the technically difficulty and the focus of research in Image-based modeling and rendering (IBMR). In this paper, a dynamic virtual environment modeling and rendering method based on the technology of catadioptric panorama is presented. The dynamic virtual environment constructed by the method mentioned above can not only realize free movement in space to some extent, but also show the visual continuous change of the virtual environment with infinite time when there is only repetitive, quasi-repetitive or statistic moving scenes.According to common flow that constructs the virtual environment with the IBMR technology, the main working in this paper includes sample capturing (chapter 2), dynamic virtual environment modeling (chapter 3) and dynamic virtual environment rendering (chapter4, 5, 6). The following is the abstract of main content:1. In this paper, catadioptric panorama is selected as sample data, and the research on sample capturing mainly focus on catadioptric panorama capturing and cylindrical unwrapping algorithm. Based on the deep research of catadioptric panorama imaging technology, a catadioptric panorama imaging device is designed and realized. An optical tracking unwrapping algorithm that unwraps the circular panorama captured by this imaging device into cylinder panorama image is presented. In order to overcome the shortcoming such as large amount of computation and poor property on real time in the above method, this paper presents a fast approximation concentric circles unwrapping algorithm and a fast eight direction symmetric reuse unwrapping algorithm.2. The dynamic virtual environment modeling method based on catadioptric panorama. Using the data of catadioptric panorama as sample, A dynamic virtual environmental expression model based on dynamic and static separating strategy is presented. It divides the dynamic virtual environment into dynamic and static area to be described separately, and then incorporates these two area with the spatial relationship. For this model, the paper presents a dynamic-static separating modeling framework, an automatic static area virtual environment modeling method based on moving capture system of the catadioptric panoramic image, a dynamic area virtual environment modeling method based on synchronic omni-directional video and a spactial relating method to the static and dynamic area.3. The dynamic virtual environment rendering method based on catadioptric panorama and its relative key technology. In this paper, the realization of dynamic virtual environment rendering is based on cylindrical view synthesis. The epipolar geometry estimation is the basis of view synthesis, so the relative key technologies of the dynamic virtual environment rendering mainly include epipolar geometry estimation and cylindrical view synthesis. In this paper, the sequence of the research is the key technology first and the rendering method later.1) The epipolar geometry estimation. An epipolar geometry estimation method based on feature matching is presented. it is the main idea of the above method that matching points set of image pairs is automatically gained to estimate the fundamental matrix, which can describes the constraint relationship of the epipolar geometry. In order to improve the precision of the sets of matching points, a feature matching method based on bidirectional maximum correlation and parallactic constraint is presented. To improve the robustness of the fundamental matrix estimation, an algorithm for fundamental matrix estimation based on swarm intelligence is presented.2) Cylindrical view synthesis. An automatic multi-step view synthesis framework is proposed, the main idea is at first automatically estimating the constraint relationship of the epipolar geometry, and then image rectification, at last view interpolation. Two cylindrical view synthesis methods are presented, one is based on planer image epipolar rectification and the other is based on cylindrical image epipolar rectification. According to comparison and analysis of experimental results from those two methods, the more suitable cylindrical view synthesis method is chosen.3) Dynamic virtual environment rendering. At first, a dynamic virtual environment generating method based on cylindrical view synthesis is presented to render the dynamic virtual environment of the current observe viewpoint and observe time. And then, the paper presents a method based on perspective projection, which quickly display the dynamic virtual environment of current observe viewpoint and observe time.Above all, this paper focuses on the core question about how to construct dynamic virtual environment,and in sequence explore catadioptric panorama capturing and cylindrical unwrapping, dynamic virtual environment modeling and rendering.