Enhanced 3D cityscape modeling for enabling the next generation geospatial web

在过去的四年里，地理空间网络(Geoweb)发展非常迅速。Geoweb是一项强大的技术，它允许人们将各种类型的网络内容连接到一个地理位置。有了geoweb，文本、图片、视频、声音等非空间网络信息都可以绑定到一个地方。Geoweb最重要的功能之一是，它允许人们在线体验和搜索物理世界。如今，谷歌地球和微软虚拟地球等3D geoweb浏览器使我们能够在全球多个特大城市之间虚拟旅行，对3D城市景观模型进行“飞越”、“得来速”和“漫游”探索。3D城市景观模型是物理城市世界的虚拟表示，因此是geoweb的重要扩展，具有许多潜在的好处。应用领域包括城市管理、规划和发展、公共安全、环境管理、旅游、电信、交通、导航和电子商务。考虑到潜在的好处，人们对照片逼真的3D城市景观模型的需求越来越大。然而，目前用于高效构建和更新3D城市景观模型的方法还不够充分，需要大幅改进。今天的典型方法是使用航空立体图像的立体3D数字化来构建这些模型。这种以人工为中心的方法对于构建正在并将在3D地理浏览器中使用的大规模3D城市模型来说效率低下且耗时过长。因此，需要新的技术、方法和策略来极大地提高3D城市景观模型生成和可视化的速度和精度，以便在大规模使用。为了应对这些新的和重要的挑战，这里提出的研究集中在：a)准确和完整的建筑立面三维重建，具有高视觉质量的立面纹理；b)根据细节层次生成3D建筑屋顶以实现动态可视化；c)整合3D室内和室外建筑模型；以及d)城市环境中典型树木的照片级真实感三维重建。

Over the past four years, the Geospatial Web (GeoWeb) has grown very quickly. The GeoWeb is a powerful technology that allows one to connect various types of web content to a geographic location. With the GeoWeb, non-spatial web information such as text, pictures, videos, sounds, etc.can all be tied to a place. One of the most significant capabilities of the GeoWeb is that it allows one to experience and search the physical world online. Today, 3D GeoWeb browsers such as Google Earth and Microsoft Virtual Earth enables us to virtually travel a number of megacities around the globe with 'fly-through', 'drive-through' and 'walk-through' explorations of 3D cityscape models. 3D cityscape models are virtual representations of the physical urban world and as such are a crucial extension of the GeoWeb that has many potential benefits. Applications include urban management, planning and development; public safety; environmental management; tourism; telecommunications; transportation; navigation; and e-commerce. Given the potential benefits there is an ever increasing demand for photo-realistic 3D cityscape models. However, current methods for efficiently building and updating 3D cityscape models are inadequate and need to be improved dramatically. Today's typical approach is to construct these models using stereo 3D digitization of aerial stereo-images. This manual-centric approach is inefficient and prohibitively time-consuming for building the large-scale 3D city models that are being, and will be, required for use in 3D geobrowsers. Thus, new techniques, methods and strategies are needed to greatly increase the speed and accuracy of 3D cityscape model generation and visualization for use at a massive scale. To address these new and important challenges, the research proposed here focuses on: a) accurate and complete 3D reconstruction of building facades with high visual quality of façade textures; b) hierarchical reconstruction of 3D building rooftops produced according to level-of-detail for dynamic visualization; c) integrating 3D indoor and outdoor building models; and d) photo-realistic 3D reconstruction of trees typical of urban settings.