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1.
Textures are an essential part of 3D building models and often consume large portions of the data volume, thus making visualization difficult. Therefore, we propose a multi-resolution texture generalization method to compress the textures of 3D building models for dynamic visualization at different scales. It consists of two steps: image compression and texture coloring. In the first step, texture images are compressed using wavelet transformation in both the horizontal and the vertical direction. In the second step, a TextureTree is created to store building texture color for dynamic visualization from different distances. To generate a TextureTree, texture images are iteratively segmented by horizontal and vertical dividing zones, until each section is basically in the same color. Then the texture of each section is represented by their main color and the TextureTree is created based on the color difference between the adjacent sections. In dynamic visualization, the suitable compressed texture images or the TextureTree nodes are selected to generate 3D scenes based on the angle and the distance between the viewpoint and the building surface. The experimental results indicate that wavelet based image compression and the proposed TextureTree can effectively represent the visual features of the textured buildings with much less data. 相似文献
2.
《International Journal of Digital Earth》2013,6(4):293-311
We address the registration problem of multisource three-dimensional (3D) human-made buildings with remote sensing images and the earth's surface in the context of virtual globes. Challenges include fast transformation of 3D coordinates with different reference systems as well as the efficient use of original model information for rigorous and accurate model registration. This paper introduces a novel fast and scalable registration approach that can establish correspondences between heterogeneous external 3D city models and images/terrain surfaces of virtual globes in an efficient and accurate manner. The approach utilizes the projected 3D feature information of 3D city models to develop robust coordinate transformation and reliable model registration methods. The proposed approach builds a solid foundation for the fusion of multisource geospatial data in a united virtual globe reference framework. We report experimental results of online registration tasks for up to over 13K buildings in an integrated 3D virtual globe platform, namely, GeoGlobe. 相似文献
3.
三维城市模型的多细节层次描述方法 总被引：11，自引：2，他引：11
以仿唐建筑群的逼真三维模型为例,介绍了一种实用的LOD模型细节层次规划及其精细程度的确定方法,以及配套的数据生产工艺,为建立具有几何上的高精度和视觉上的高逼真度的三维城市模型提供了一条有效的途径。 相似文献
4.
建筑物的三维建模是城市三维建模和可视化的重要组成部分。本文提出一种基于点云数据与遥感图像的建筑物三维模型快速建模方法。首先,运用改进的RANSAC法从点云数据中提取建筑立面,根据立面区分平顶建筑与人字形屋顶建筑;在此基础上,进一步对建筑物的高度进行提取;之后,利用区域增长法从遥感图像中提取建筑物屋顶轮廓,利用形态学方法对提取出的轮廓进行规则化处理,并基于Freeman链码提取轮廓角点,得到规整的轮廓;最后,根据提取出的建筑高度属性对屋顶轮廓拉伸并进行纹理映射,实现对建筑物的三维重建。通过实例证明,提出的方法能快速、高效地实现建筑物三维模型的重建。 相似文献
5.
针对城市侧视地图上建筑物轮廓线主要依靠人工交互提取,成本高昂、效率低下且精细度和准确度有限的问题,提出了一种任意视角侧视地图中建筑物轮廓线的自动提取方法。采用深度缓冲区分割算法获取单个建筑物对象的颜色缓冲区,顾及了存在建筑群的情况和建筑物密集区域的遮挡问题,再基于颜色缓冲区追踪建筑物轮廓线。为了保持遮挡一致性且便于匹配提取出的矢量轮廓线与栅格侧视地图,本文还提出了基于投影空间分块加载三维城市模型的方法。最后,以武汉市典型三维城市模型数据为例,证明了该方法的有效性和可靠性。 相似文献
6.
City model enrichment 总被引：1，自引：0，他引：1
Philip D. Smart Jonathan A. Quinn Christopher B. Jones 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(2):223-234
The combination of mobile communication technology with location and orientation aware digital cameras has introduced increasing interest in the exploitation of 3D city models for applications such as augmented reality and automated image captioning. The effectiveness of such applications is, at present, severely limited by the often poor quality of semantic annotation of the 3D models. In this paper, we show how freely available sources of georeferenced Web 2.0 information can be used for automated enrichment of 3D city models. Point referenced names of prominent buildings and landmarks mined from Wikipedia articles and from the OpenStreetMaps digital map and Geonames gazetteer have been matched to the 2D ground plan geometry of a 3D city model. In order to address the ambiguities that arise in the associations between these sources and the city model, we present procedures to merge potentially related buildings and implement fuzzy matching between reference points and building polygons. An experimental evaluation demonstrates the effectiveness of the presented methods. 相似文献
7.
3维景观模型越来越广泛地应用于城市建设和管理之中,如何高效快速地构建城市3维景观模型成为一个关键技术问题。地形与地物分层建模法是城市3维景观模型重建领域中的一个热门方法,它采用地形数据叠加建筑物实体来构建3维景观。该方法已成功应用于惠州市3维建模,实践证明该方法建模速度快、操作简单、具有广阔的应用前景。 相似文献
8.
Sandra Loch-Dehbi Lutz Plümer 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(2):177-187
This paper presents a novel approach to automated geometric reasoning for 3D building models. Geometric constraints like orthogonality or parallelity play a prominent role in man-made objects such as buildings. Thus, constraint based modelling, that specifies buildings by their individual components and the constraints between them, is a common approach in 3D city models. Since prototyped building models allow one to incorporate a priori knowledge they support the 3D reconstruction of buildings from point clouds and allow the construction of virtual cities. However, high level building models have a high degree of complexity and consequently are not easily manageable. Interactive tools are needed which facilitate the development of consistent models that, for instance, do not entail internal logical contradictions. Furthermore, there is often an interest in a compact, redundancy-free representation. We propose an approach that uses algebraic methods to prove that a constraint is deducible from a set of premises. While automated reasoning in 2D models is practical, a substantial increase in complexity can be observed in the transition to the three-dimensional space. Apart from that, algebraic theorem provers are restricted to crisp constraints so far. Thus, they are unable to handle quality issues, which are, however, an important aspect of GIS data and models. In this article we present an approach to automatic 3D reasoning which explicitly addresses uncertainty. Hereby, our aim is to support the interactive modelling of 3D city models and the automatic reconstruction of buildings. Geometric constraints are represented by multivariate polynomials whereas algebraic reasoning is based on Wu’s method of pseudodivision and characteristic sets. The reasoning process is further supported by logical inference rules. In order to cope with uncertainty and to address quality issues the reasoner integrates uncertain projective geometry and statistical hypothesis tests. Consequently, it allows one to derive uncertain conclusions from uncertain premises. The quality of such conclusions is quantified in a way which is sound both from a logical and a statistical perspective. 相似文献
9.
10.
一种3维建筑物模型的数据描述及采集方案 总被引：1，自引：0，他引：1
随着“数字地球”、“数字城市”概念的不断深化,作为“数字城市”最基础、最关键的技术,3维城市模型数据的制作已经成为数字化测绘的新技术亮点。本文介绍了一种3维城市建筑物模型的数据存储结构,详细阐述了不同类型3维建筑物的采集方法,由此总结出3维建筑物模型数据的生产、存储、表述的完整方案。 相似文献
11.
ABSTRACTCity models have a wide variety of uses that require different kind of data representation or data models. Having a dynamic model that enables picking the right representations (meshes, volumetric data, point cloud, etc.) can prove useful to adapt an application to each user's needs. In this paper, we present an original method to create personalised visualisations of 3D city models on the fly. By organising the server data in a hierarchy of tiles, we are able to generate personalised models based on the user's preferences. These preferences take the shape of a set of rules that apply to each tile or city object and allow the user to choose which representation of the object to use depending on its position or semantic information (classification, height, etc.). Our method is designed around existing standards, guaranteeing the interoperability of the produced models. 相似文献
12.
Pawel Boguslawski Christopher M. Gold 《ISPRS Journal of Photogrammetry and Remote Sensing》2011,66(2):188-197
While CityGML permits us to represent 3D city models, its use for applications where spatial analysis and/or real-time modifications are required is limited since at this moment the possibility to store topological relationships between the elements is rather limited and often not exploited. We present in this paper a new topological data structure, the dual half-edge (DHE), which permits us to represent the topology of 3D buildings (including their interiors) and of the surrounding terrain. It is based on the idea of simultaneously storing a graph in 3D space and its dual graph, and to link the two. We propose Euler-type operators for incrementally constructing 3D models (for adding individual edges, faces and volumes to the model while updating the dual structure simultaneously), and we also propose navigation operators to move from a given point to all the connected planes or polyhedra for example. The DHE also permits us to store attributes to any element. We have implemented the DHE and have tested it with different CityGML models. Our technique allows us to handle important query types, for example finding the nearest exterior exit to a given room, as in disaster management planning. As the structure is locally modifiable the model may be adapted whenever a particular pathway is no longer available. The proposed DHE structure adds significant analytic value to the increasingly popular CityGML model. 相似文献
13.
3D city models offered by digital map providers typically consist of several thousands or even millions of individual buildings. Those buildings are usually generated in an automated fashion from high resolution cadastral and remote sensing data and can be very detailed. However, not in every application such a high degree of detail is desirable. One way to remove complexity is to aggregate individual buildings, simplify the ground plan and assign an appropriate average building height. This task is computationally complex because it includes the combinatorial optimization problem of determining which subset of the original set of buildings should best be aggregated to meet the demands of an application.In this article, we introduce approaches to express different aspects of the aggregation of LoD 1 building models in the form of Mixed Integer Programming (MIP) problems. The advantage of this approach is that for linear (and some quadratic) MIP problems, sophisticated software exists to find exact solutions (global optima) with reasonable effort. We also propose two different heuristic approaches based on the region growing strategy and evaluate their potential for optimization by comparing their performance to a MIP-based approach. 相似文献
14.
Texture mapping generates photorealistic representations of three‐dimensional (3D) geometric objects and enhances the spatial perception of areas of interest. Over the past two decades, even though various approaches for 3D urban models have been investigated, their use has been limited because of the lack of spatial accuracy, details, and the complex processes. It is difficult to maintain highly detailed texture information without using a hybrid of aerial image and ground‐based imaging techniques, which are costly. Furthermore, it is hard to develop a fully automated process for 3D urban mapping that achieves high spatial accuracy. With regard to the issues, this research aims to develop a semi‐automated process for 3D building models that would help image‐based approaches. It helps acquire qualified texture information and improve the appearance of building façades in a large city. In particular, this research first investigates an optimal overlap of consecutive aerial images that generates sufficient information to texture each façade, thus making this process more cost‐effective. Second, this research develops an application to semi‐automatically build 3D buildings and textured 3D buildings. The application is developed in C++. The textured 3D building models are quantitatively and qualitatively assessed to determine the usability of the semi‐automated process. 相似文献
15.
AbstractWith the rapid development of 3D Digital City, the focus of research has shifted from 3D city modeling and geo-database construction to 3D geo-database service and maintenance. The frequent modifications on geometry, texture, attribute, and topology present a great challenge to the 3D geo-database updating. This article proposes an event-driven spatiotemporal database model (ESDM) that combines the historical and present 3D city models with the semantic classification and state expression, triggered by changing events predefined. In addition, a corresponding dynamic updating method based on adaptive matching algorithm is presented to perform the dynamic updating operation for the complex 3D city models automatically, according to the compound matching of semantics, attributes, and spatial locations. Finally, the validity and feasibility of the proposed ESDM and its updating method are demonstrated through a 3D geo-database with more than 1.5 million 3D city models. 相似文献
16.
3D city models are widely used in many disciplines and applications, such as urban planning, disaster management, and environmental simulation. Usually, the terrain and embedded objects like buildings are taken into consideration. A consistent model integrating these elements is vital for GIS analysis, especially if the geometry is accompanied by the topological relations between neighboring objects. Such a model allows for more efficient and errorless analysis. The memory consumption is another crucial aspect when the wide area of a city is considered – light models are highly desirable. Three methods of the terrain representation using the geometrical–topological data structure – the dual half-edge – are proposed in this article. The integration of buildings and other structures like bridges with the terrain is also presented. 相似文献
17.
基于Skyline的三维城市模型数据库管理系统设计与实现 总被引：1，自引：0，他引：1
黄梦龙 《测绘与空间地理信息》2014,(8):133-135
城市三维模型在城市规划、建设等方面得到了广泛的应用。本文介绍了城市三维模型管理的现状,分析了三维城市模型建库管理的需求,基于Skyline三维地理信息系统和ArcGIS Engine,设计了三维模型数据库的存储结构,并开发了三维模型数据库管理系统,实现了三维模型的建库管理。 相似文献
18.
Due to the fast development of the urban environment, the need for efficient maintenance and updating of 3D building models is ever increasing. Change detection is an essential step to spot the changed area for data (map/3D models) updating and urban monitoring. Traditional methods based on 2D images are no longer suitable for change detection in building scale, owing to the increased spectral variability of the building roofs and larger perspective distortion of the very high resolution (VHR) imagery. Change detection in 3D is increasingly being investigated using airborne laser scanning data or matched Digital Surface Models (DSM), but rare study has been conducted regarding to change detection on 3D city models with VHR images, which is more informative but meanwhile more complicated. This is due to the fact that the 3D models are abstracted geometric representation of the urban reality, while the VHR images record everything. In this paper, a novel method is proposed to detect changes directly on LOD (Level of Detail) 2 building models with VHR spaceborne stereo images from a different date, with particular focus on addressing the special characteristics of the 3D models. In the first step, the 3D building models are projected onto a raster grid, encoded with building object, terrain object, and planar faces. The DSM is extracted from the stereo imagery by hierarchical semi-global matching (SGM). In the second step, a multi-channel change indicator is extracted between the 3D models and stereo images, considering the inherent geometric consistency (IGC), height difference, and texture similarity for each planar face. Each channel of the indicator is then clustered with the Self-organizing Map (SOM), with “change”, “non-change” and “uncertain change” status labeled through a voting strategy. The “uncertain changes” are then determined with a Markov Random Field (MRF) analysis considering the geometric relationship between faces. In the third step, buildings are extracted combining the multispectral images and the DSM by morphological operators, and the new buildings are determined by excluding the verified unchanged buildings from the second step. Both the synthetic experiment with Worldview-2 stereo imagery and the real experiment with IKONOS stereo imagery are carried out to demonstrate the effectiveness of the proposed method. It is shown that the proposed method can be applied as an effective way to monitoring the building changes, as well as updating 3D models from one epoch to the other. 相似文献
19.
《International Journal of Digital Earth》2013,6(1):88-106
Abstract Digital Earth essentially consists of 3D and moreD models and attached semantic information (attributes). Techniques for generating such models efficiently are required very urgently. Reality-based 3D modelling using images as prime data source plays an important role in this context. Images contain a wealth of information that can be advantageously used for model generation. Images are increasingly available from satellite, aerial and terrestrial platforms. This contribution briefly describes some of the problems which we encounter if the process of model generation is to be automatised. With the help of some examples from Digital Terrain Model generation, Cultural Heritage and 3D city modelling we show briefly what can be achieved. Special attention is directed towards the use of model helicopters for image data acquisition. Some problems with interactive visualisation are discussed. Also, issues surrounding R&D, professional practice and education are also addressed. 相似文献