共查询到19条相似文献，搜索用时 515 毫秒
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《武汉大学学报(信息科学版)》2020,(2)
传统的可视域分析方法需借助高精度三维模型,而目前三维模型构建的自动化水平、精度和完整度等很难满足道路环境可视域分析的要求。车载激光扫描系统可以高速度、高密度、高精度地获取道路及两侧地物的位置和属性信息(如反射强度、回波波形等),为大规模道路场景可视域计算与分析提供了一种全新的技术手段。借助深度缓存算法,提出了一种基于三维激光点云数据的可视域快速、稳健计算方法。该方法在典型道路地物要素提取的基础上,动态构建视场空间索引,实现了道路场景中任意位置可视域的快速、稳健估计,可广泛应用于交通标志牌遮挡分析、路灯有效照明区域计算和建筑物可视绿地面积估计等,为基础设施科学安置及运行健康状况监测、城市形态分析与城市规划等提供科学的辅助决策。 相似文献
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当前GIS软件中通视分析建立在DEM数据基础上,而DEM中不含植被和建筑物信息,从而会造成通视分析误差。通过Li DAR点云数据获取高精度植被和建筑物高度,提出一种顾及地物的插值算法,生成同一网格大小的DEM与DSM,在其上分别进行通视域分析,并将分析结果进行对比,发现DEM比DSM更容易扩大视域范围,从而产生了分析误差,验证了利用DSM进行通视分析的可行性。 相似文献
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《测绘》2019,(4)
当前建筑信息模型(BIM)已成为网络三维地理场景(3D WebGIS)的重要数据来源。针对BIM模型与3D WebGIS集成时存在单体模型数据量大、模型渲染不流畅等问题,本文以建筑信息模型的数据转换与数据调度为研究内容,提出了一种基于三维瓦片(3D Tiles)的BIM模型转换方案,该方案首先将BIM模型转换为工业基础类(IFC)标准格式并对模型进行拆分,然后对拆分后的建筑部件模型进行分类并转换为三维瓦片。设计了结合视锥体与视点的动态数据调度算法,该算法首先通过视域剔除得到视锥体内所需渲染的瓦片,再通过基于视点的动态调度算法对所需瓦片进行调度。最后以某建筑群BIM模型作为实验数据进行实验分析,并开发了原型系统,验证了本文研究方法的可行性。 相似文献
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视觉效果是城市规划需要考虑的重要要素之一.基于3 DGIS的计算机技术可以用于定量分析城市三维景观空间的可视性.本文介绍了可视性分析应用于城市规划的流程,提出了针对地形和建筑物可视性分析的数学几何模型.在地形可视性分析模型中,采用了一种结合水平投影和高程插值计算的方法判断地形上两点之间的通视性;在建筑物可视性分析中,采... 相似文献
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运用数学建模的方式,对山地丘陵地理环境中任意多点在特定高度的可视范围进行了研究.通过计算单一观察点与周围地形的切点集合,构成单点通视锥面,求出该观察点在特定高度的通视范围轮廓,再对多点的通视范围轮廓进行合并,并对整个通视轮廓取样进行光滑;最后形成山地丘陵环境中多点在特定高度的通视范围. 相似文献
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刘亚洲邓安健 《测绘与空间地理信息》2023,(11):51-54
为了提高目前机载LiDAR点云数据滤波和建筑物提取精度,本文提出一种基于超体素的点云滤波与建筑物提取方法。对每个超体素进行相似性判断来实现向上一层的区域增长式合并,并通过判断超体素簇与邻接超体素簇的凹凸性实现再向上一层的合并,最终通过计算聚类对象自身几何特征来过滤地面、植被和噪声,从而得到建筑物点云。实验利用ISPRS公布的标准数据集,选择3个地形数据进行实验。实验结果表明本文算法滤波性能更好,建筑物提取结果优于专业点云处理软件的提取结果。 相似文献
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GIS技术在景观视觉分析中的应用 总被引：6，自引：0，他引：6
探索应用地理信息系统空间分析技术,通过三维数字高程模型修正模拟规划在建大型建筑群的“地形”表面,并对观察点和目标点之间视觉的通视、可视域分析,采用定性和定量相结合的方法,形象直观分析评价未来重庆科技馆的景观视觉效果, 相似文献
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森林防火监测站选址及可视域分析 总被引：1，自引：0，他引：1
火灾是森林的宿敌,危害巨大。建立监测站不仅是一种有效的森林防火措施,还是我国主流的预防对策。文章基于GIS对某林区数字高程模型进行空间分析,通过分区查询统计理论提取其最高点,利用缓冲区技术去除不合理高程点,获取可视域范围较大的监测站点分布图;根据泰森多边形对监测站点监测区域进行可视域分析,获取其可视域分析指标值,同时剔除功能重复的站点,以得到其较为理想的分布。该方法只需单一的数字高程模型数据,选取站点过程考虑综合因素,可操作性强,为森林防火监测站的部署和分析提供了一种科学参考。 相似文献
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In this work we investigate the effectiveness of different types of visibility models for use within location‐based services. This article outlines the methodology and results for our experiments, which were designed to understand the accuracy and effects of model choices for mobile visibility querying. Harnessing a novel mobile media consumption and authoring application called Zapp, the levels of accuracy of various digital surface representations used by a line of sight visibility algorithm are extensively examined by statistically assessing randomly sampled viewing sites across the 1 km2 study area, in relation to points of interest (POI) across the University of Nottingham campus. Testing was carried out on three different surface models derived from 0.5 m LiDAR data by visiting physical sites on each surface model with 14 random point of interest masks being viewed from between 10 and 16 different locations, totalling 190 data points. Each site was ground‐truthed by determining whether a given POI could be seen by the user and could also be identified by the mobile device. Our experiments in a semi‐urban area show that choice of surface model has important implications for mobile applications that utilize visibility in geospatial query operations. 相似文献
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Point-based and object-based building extractions were conducted in airborne LiDAR data in a sample area of Buffalo, New York. First, the earth surface points were filtered from the entire laser scan data set using a new filtering algorithm, which combines the TIN slope modelling and statistical analysis. The off-ground points were extracted for buildings in the study area using both point cluster analysis and object-oriented classifications. The accuracies of both approaches were tested using the digitised ground truth. The outcomes of accuracy testing of the point-based method are correctness: 88.74%, completeness: 92.67% and quality: 83.50%. The results of the accuracy of object-based building extraction are correctness: 87.21%, completeness: 60.14%, and quality: 55.26%. Reconstructions of 3D building models based on the extracted building points were performed. This study contributes scientific and technological knowledge for researchers in developing more effective methods in converting the LiDAR survey to a 3D GIS database. 相似文献
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Yixiang Tian Markus Gerke George Vosselman Qing Zhu 《ISPRS Journal of Photogrammetry and Remote Sensing》2010,65(4):395-408
The paper presents an automatic method for the reconstruction of building models from video image sequences. These videos may be recorded using a hand-held camera or a camera mounted on a moving car. Such terrestrial video sequences are economic and flexible. Presenting buildings as geometric models–rather than for instance a representation from a simple meshing of 3D points–enables one to perform a wide range of analyses. However, sparse 3D points and 3D edges do not contain topological relations. Therefore, integrating building structure knowledge into the reconstruction steps plays an important role in our method. First, some rules are applied to reasonably group the extracted features. Then, a suitable outline and normal direction are specified for each surface patch. Based on these surface patches, a hybrid model- and data-driven method is used to recover a building model from both the extracted surface patches and hypothesized parts. Using the building structure knowledge leads to a simple and fast reconstruction method, and also enables one to obtain the main structures of buildings. The results show that this method correctly sets up topological relationships between generated surface patches and also obtains reasonable structure models in occluded areas. Therefore, the reconstructed models satisfy requirements for both visualization and analysis. 相似文献
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利用将建筑实体进行高度抽象，提出了建筑点群，以GIS的空间分析理论为依据，通过实体高度、起伏度、空间聚集度三个指标对城市的3维形态进行量化与分析。选取南京市主城区为实验样区，提取该区域的建筑点群，用三个指标对实验样区内3维形态的空间分布格局和时间发展特点进行定量分析与描述。实验结果证明，这三个指标从不同角度分析了建筑实体在区域内的组合方式，能够在一定程度上反映城市3维形态的基本特征，有助于对城市空间分布格局及城市历史演变过程的研究。 相似文献
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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
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随着三维激光点云数据获取能力的提升，基于三维激光点云进行建筑物模型重建与立面测绘成为工程应用中常用的方法。三维激光点云数据能够体现建筑物丰富和直观的细节信息，然而海量数据处理给建筑物模型构建带来了极大挑战。本文通过对建筑物的三维激光点云数据进行横切得到建筑物轮廓点，并采用基于遗传算法的TSP算法对轮廓点进行处理以获取建筑物各立面的方程系数，最终实现建筑物模型的构建和获取详细的建筑物立面数据。试验结果表明，此方法可以较好地实现LOD1级建筑物模型的构建，进而为更高（LOD3）级别的建筑物模型构建提供依据。 相似文献
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利用机载LiDAR点云数据进行建筑物重建是当今摄影测量与遥感领域的一个热点问题,特别是复杂形状建筑物模型的精确自动构建一直是一个难题。本文提出一种基于关键点检测的复杂建筑物模型自动重建方法,采用RANSAC法与距离法相结合的分割方法自动提取建筑物屋顶各个平面的点云,并利用Alpha Shape算法提取出各个平面的精确轮廓,根据屋顶平面之间的空间拓扑关系分析建筑物的公共交线特征,在此特征约束下对提取的初始关键点进行修正,最终重建出精确的建筑物3维模型。选取不同类型复杂建筑物与包含复杂建筑物的城市区域点云进行实验,结果表明该算法具有较强实用价值。 相似文献
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面向数字城市和智慧城市建设急需城市建筑三维模型支撑的需要，本文基于机载LiDAR数据，以“顾及平整性的屋顶面片分割—屋顶层间连接—三维模型重建”为脉络，提出了一种采用层间连接和平滑策略的建筑屋顶三维模型重建方法。在屋顶面片提取过程中，充分顾及了屋顶面片的平整性；并在屋顶面片平整基础上，提出层间连接点的概念，以实现高效、快速的模型重建工作。试验部分，本文从屋顶面片重建完整率与正确率、重建几何精度及建筑物高程对于重建的影响3个方面作了较为详尽的评价与分析，并在国际摄影测量与遥感学会标准数据集支撑下，与国际同行进行试验对比。试验结果表明，建筑屋顶重建的完整率和正确率分别达到90%和95%；在偏移距离评价方面，平均偏移距离和标准差最优分别达0.05 m和0.18 m。因此，本文方法可有效完成建筑屋顶三维模型重建，重建模型准确度高、完整性好。 相似文献
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The complexity of building models directly affects the application efficiencies of 3D urban maps. To address the challenges of building models with various structures, we propose a structural simplification method in this paper. The geometric structures of building models are classified into three categories: embedded structures, compositional structures, and connecting structures, which can be extracted separately through convex/concave analysis. Some specific rules are proposed for the simplification of geometric structures, and the building models are suggested to be simplified progressively. The robustness and efficiency of the method are demonstrated by experiments, and the applications of the Levels of detail of the building models are illustrated. 相似文献