基于倾斜摄影的多目标纹理最优化研究

发布时间：2018-04-11 11:34

本文选题：倾斜影像 + 最优纹理选取　；参考：《桂林理工大学》2017年硕士论文

【摘要】：随着城市数字化的不断发展,构建城市三维模型已成为摄影测量、计算机视觉等领域的研究热点之一。近年来,无人机倾斜摄影这一高新技术的出现,为三维建模提供了很好的数据来源,无人机倾斜摄影技术不同于传统的垂直摄影技术,它将垂直摄影与倾斜摄影两者相结合,多视角的获取地物信息,不仅在数据采集方面减少了野外工作量,而且在纹理信息方面增大了墙面纹理的采集量。在城市建筑物三维模型的重建过程中,纹理作为构建真实感三维模型的重要组成部分,纹理质量的好坏直接影响了模型的效果,故在纹理映射过程中,最优纹理的选取至关重要,如何选取高质量、高真实感的纹理成为了研究重点。因此,本文针对目前国内外三维重建纹理映射的研究现状,对基于无人机倾斜影像的城市三维模型纹理映射进行了研究,提出了一个选取最优纹理的算法,该算法通过构建纹理最优化模型来选取最优纹理,不仅提高了建模的速度,而且加强了纹理的真实感,具有重大的研究价值。本文提出的基于倾斜摄影的纹理优化及城市三维纹理映射主要工作有以下几个方面:首先,对无人机倾斜摄影系统中的多旋翼无人机与倾斜摄影相机进行了深入研究,重点分析了倾斜摄影的成像方式,并阐述了选择倾斜影像作为纹理源的优势,从而论述了选取最优纹理的必要性。其次,阐述了建筑物最优纹理选取的方法,主要将纹理分为顶面与墙面两个部分进行选取,提出了一种构建墙面纹理最优化模型的算法,该算法通过模型的约束条件与目标函数对墙面纹理择优选取,详细阐述了最优化模型的约束条件和目标函数,从而构建了多目标墙面纹理最优化模型,最后对最优化模型的求解过程进行了详细阐述。然后,对纹理映射的方法进行了回顾,通过分析与对比对纹理映射过程进行了优化,先将建筑物模型与影像匹配,利用最优化模型选取最优纹理,再对选取出的纹理存在树木遮挡的情况进行处理与恢复。利用OpenGL将最优纹理图像映射到三维建筑物表面上,实现建筑物三维模型的纹理映射。最后,针对本文提出的方法,采用无人机倾斜摄影测量技术获取的倾斜影像进行实验,通过对建筑物纹理进行最优选取,将影像中最优纹理的坐标归一化后,将其最优纹理映射到建筑物三维模型表面,得到了带有真实感纹理的城市建筑物三维模型,证明了本文的方法在提高建筑物纹理真实感上的有效性。
[Abstract]:With the constant development of city digitization, the construction of urban 3D model has become one of the research hotspots in the field of photogrammetry, computer vision and so on.In recent years, the emergence of tilt photography of UAV provides a good data source for 3D modeling. The tilt photography of UAV is different from the traditional vertical photography, which combines vertical photography and tilt photography.The multi-angle acquisition not only reduces the workload in the field of data acquisition, but also increases the collection of metope texture in the aspect of texture information.In the process of reconstruction of 3D model of urban buildings, texture is an important part of constructing realistic 3D model, the quality of texture directly affects the effect of the model, so in the process of texture mapping,The selection of optimal texture is very important. How to select high quality and realistic texture has become the focus of research.Therefore, according to the current situation of 3D reconstruction texture mapping at home and abroad, this paper studies the urban 3D model texture mapping based on UAV tilt image, and proposes an algorithm to select the optimal texture.The algorithm not only improves the speed of modeling, but also strengthens the realistic texture by constructing the optimal texture model to select the optimal texture, which has great research value.The main work of this paper is as follows: firstly, the multi-rotor UAV and tilt camera in UAV tilt photography system are studied deeply.In this paper, the imaging methods of oblique photography are analyzed, and the advantages of choosing tilted image as texture source are expounded, and the necessity of selecting optimal texture is discussed.Secondly, this paper expounds the method of selecting the optimal texture of the building, mainly divides the texture into two parts, the top and the wall, and puts forward an algorithm to construct the optimal model of the texture of the wall.In this algorithm, the constraints and objective functions of the optimization model are discussed in detail, and the multi-objective texture optimization model is constructed by selecting the optimal metope texture by the constraint condition and objective function of the model.Finally, the process of solving the optimization model is described in detail.Then, the methods of texture mapping are reviewed, and the process of texture mapping is optimized by analyzing and comparing. Firstly, the building model is matched with the image, and the optimal texture is selected by using the optimization model.Then processing and restoring the selected texture with tree occlusion.The optimal texture image is mapped to the 3D building surface by OpenGL, and the texture mapping of the 3D building model is realized.Finally, aiming at the method proposed in this paper, the tilt image obtained by UAV tilt photogrammetry is experimented, and the coordinate of the optimal texture in the image is normalized by the optimal selection of the texture of the building.By mapping the optimal texture to the surface of the 3D model of a building, a 3D model of a city building with realistic texture is obtained, which proves the effectiveness of the proposed method in improving the realistic texture of the building.
【学位授予单位】：桂林理工大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P23

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