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基于航空立体影像对的人工目标三维提取与重建
3D Extraction and Reconstruction of Manmade Objects Based on Stereo Image Pair
【作者】 邵振峰;
【导师】 李德仁;
【作者基本信息】 武汉大学 , 摄影测量与遥感, 2004, 博士
【摘要】 随着空间技术、计算机技术、通讯技术的飞速发展,以全球定位系统(GPS)、遥感(RS)和地理信息系统(GIS)为核心的现代测绘学科也日益向数字化、自动化和实时化方向发展。在空间数据获取方面,获取地球表面高分辨率、高精度、多时相、多光谱数字影像的技术已日趋成熟并得到广泛应用,特别是数字摄影测量技术的发展为获取现实世界中物体的三维模型提供了极大的方便,从而使数字城市的建设和发展成为可能。但同时,基于影像的数据处理的理论和算法还相对滞后,基于影像的特征提取技术是整个社会信息化过程中面临的重要问题,因此,基于影像的三维重建技术是摄影测量的核心任务之一,同时也是计算机视觉的基本任务之一。当前,基于航空影像的人工目标三维提取和重建已成为摄影测量与遥感领域和计算机视觉领域共同关注的国际前沿课题,对这一课题的研究有着重要的理论和现实意义。 本文着重探讨基于航空立体影像对的人工地物三维提取和重建的理论与方法,并研究开发了一体化立体影像平台。基于此平台,作者对几种典型人工目标的三维提取和重建进行了系统的尝试和深入的探讨,在理论与实践上提出并实现了一系列有实际应用价值的方法和算法。主要内容分五个方面:一体化立体影像平台的建立;三维重建拓扑数据模型的建立;简单房屋半自动提取和三维重建;复杂房屋三维重建;立交桥半自动提取和三维重建,五个部分分别对应本文的第二章到第六章。 (1)一体化影像平台的建立 目前的三维重建软件中普遍存在的一个局限性就是数据采集和三维模型重建平台的脱节,人工采集数据、人工建立拓扑关系加上人工编辑的建模思路,使得整个建模过程费时费力,效率低下。本文提出了三维数据获取和重建集成的三维建模策略,并实现了实验平台。作者从原始影像开始,实现了立体像对的自动内定向、自动相对定向、核线重采样和立体影像对的生成,并同本文实现的自动半自动提取和重建算法相结合,在统一的集成式平台上实现人工地物的半自动提取与三维重建。该部分的核心是采用SUSAN角点检测算子在左右影像上分别提取特征点,并实现了金字塔影像匹配,求得同名点的精确位置,从而实现了航空立体影像对的自动相对定向,算法稳定可靠,为后续章节的边缘提取和模型重建提供了平台保证。 (2)三维重建数据模型的建立 地理信息系统中数据模型的目的和作用是用于描述现实世界中的实体和对象,三维空间数据模型是实现三维重建的基础,本部分在系统总结三维数据模型研究现状的基础上,探讨人工地物三维重建数据模型,该部分提出的拓扑数据模型为后续章节的具体重建工作提供了抽象的概要模型设计。 空间数据模型的一个重要特性是对空间关系的描述和表达,空间关系研究中的一个重要方面是拓扑关系的研究,对象之间拓扑关系是对模型进行分析和研究的基础。在三维空间内,三维空间拓扑关系的研究相对滞后,在很大程度上限制了三维GIS的进一步发展,尤其是对三维数学模型研究发展的限制。本部分在对拓扑学系统研究的基础上,总结了拓扑关系在三维重建中的作用。在二维拓扑学研究的基础上,对三维拓扑学展开研究,并从人工地物三维重建的角度,将人工地物的三维拓扑分为内拓扑和外拓扑,创造性地定义了拓扑链和三维拓扑连通度的概念,用于描述人工地物三维拓扑。基于对三维拓扑的研究展开对拓扑数据模型的探讨,深入分析当前典型的拓扑数据模型的踌澄,,。发展及研究现状,并总结目前拓扑数据模型研究方面尚存在的主要问题和实现难点,提出面向地学应用的三维重建拓扑数据模型。在分析三维重建的信息传输模式的基础上,剖析三维重建中拓扑关系建立的内涵,采取结合度量关系的拓扑关系重建方法,建立了人工地物三维重建的拓扑数据模型。 (3)筒单房屋半自动提取和三维重建 房屋三维模型是数字城市中一类极为重要的数据模型,如何有效的表现房屋模型,使其能够满足三维表现和空间分析的要求是一个鱼待解决的问题。不同地域的房屋具有不同的建筑风格,从三维重建的角度,本文首先对房屋进行分类,并对简单房屋和复杂房屋采用不同的提取和重建策略,实现简单型房屋半自动提取和自动三维重建,从而使三维重建的效率得到一定提高。 在详细讨论和比较多种基于影像的直线特征提取算法的基础上,本文采用了基于canny边缘检汀’测算子结合直线模板提取房屋直线边缘的整体策略,实现了基于支持区域的影像直线特征同名匹配,并结合最小二乘平差实现了解算直线段精确位置的算法。利用立体核线影像的约束条件结合房屋自身的几何限制条件实现简单房屋三维模型的半自动重建。设计并实现了从立体航空影像对提取和重建简单房屋三维模型的实验系统。 (4)复杂房屋三维重建 复杂房屋的三维重建目前完全依赖人工操作来完成,其难度和工作量之巨大成为城市建筑物三维建模的“瓶颈”所在。因此,研究复杂房屋的三维自动半自动重建对于三维城市模型的构建乃至整个数字城市的建设都有着不言而喻的作用。本文对从航空立体影像对重建复杂房屋作了尝试性的研究和探讨,首先采用拓扑链概念来描述?
【Abstract】 Driven by the development of computer science, communication and spatial technologies, modern geomatics, whose kernel is 3S technologies, is developing towards digitization, automation and real-time with high speed. In the aspect of data acquisition, technologies of acquiring digital images with high-resolution and multi-band are becoming more and more mature and have gotten extended application. Especially, the development of digital photogrammetry greatly facilitates spatial information extraction and of the real world objects to a great extent and further promotes the construction and development of Cyber City. But the theory and algorithm of data processing and analysis based on images are lag correspondingly and feature extraction based on images is the main barrier of faced by information age. 3D reconstruction based on image is one of the core tasks of photogrammetry, and also is one of the basic missions of computer visualization research field. Therefore, 3D extraction and reconstruction of manmade objects has gotten international attention in photogrammetry, remote sensing and computer vision and research on it is significant in theory and in practice as well.This paper mainly focuses on theories and methods of 3D extraction and reconstruction of manmade objects based on stereo image pair and integrated platform implementation. Based on the integrated platform, mis paper attempts to research 3D extraction and reconstruction methods of several different kinds of manmade objects based on stereo image pair and corresponding methods and algorithms that are valuable in practical application thoughtfully. Main research and concrete works can be concluded as five aspects as follows:1. Developing of integrated platform for data collection and 3D modelingA common default exists in current software of 3D reconstruction is the disjointedness between data collection and 3D model reconstruction. The process of manual data collection, topologicai relation building and editing is the main reason of low efficiency. This paper presents a strategy of 3D data acquisition and reconstruction and develops an experimental platform that can integrate data collection and 3D modeling together. The whole procedure, from original image data acquiring, automatic interior orientation, automatic relative orientation and epipolar image sampling to stereo image pair generation, combined with automatic and semi-automatic extraction and reconstruction can be realized by an integrated platform. A main idea of this strategy is using SUSAN operator to perform the relative orientation and the reliability is validated through experimental results. In a word, this integrated platform provides an excellent environment for the following research and work.2. Establishing of 3D reconstruction data modelIn GIS, one of the most important role of data model is to describe entities and objects in real world as true as possible. 3D data modeling is the base of 3D reconstruction. Based on summarizing state-of-the-arts of 3D data model, this paper studies the problem of 3D reconstruction data model for manmade objects. 3D topologicai data mode presented in this paper provides an abstract outline model design for following 3D reconstruction.An important function of spatial data model is the ability of spatial relation description and representation and an important aspect of spatial relation is topologic relation. In 3D space, the study of topological relation is lag, which restricts the development of 3D GIS to a great extent. This paper summarizes the role of topological relation in 3D reconstruction based on the study of topology. After analyzing 2D topology, this paper focuses on the study of 3D topology from the angle of 3D reconstruction. In this paper, 3D topology of manmade objects is classified into interior topology and outer topology and several important concepts including topological chain and 3D topological connection degree are presented and defined to describe the 3D topological relation between manmade objects. Then a new topo