高分辨率遥感影像的建筑物自动提取

文章结合结构图分析方法,提出一种针对高分辨率遥感影像中建筑物自动提取方法.该方法利用几何限制对线基元进行初连接,解决由于边缘检测无法完整提取建筑外边缘问题;通过构造结构图确立线基元之间连接关系,搜索结构图中闭合路径,建立高级别特征,对过于散列的线基元进行整合;在此基础上,综合考虑建筑物的几何结构、光谱特征等图像信息筛选闭合路径,实现对建筑物的提取.最后通过对天绘一号高分辨率遥感影像进行建筑物自动提取验证了该方法的有效性.     

融合颜色和纹理特征的彩色图像分割

根据高分辨率遥感影像中地物呈高斯分布的特性,文章将水平集与Bayesian统计理论相结合,提出一种统计理论框架下的广义水平集分割模型;并利用多元高斯分布融合图像的颜色和纹理信息,实现彩色图像的分割及建筑物目标提取.实验结果表明,该模型实现了与eCognition软件中多尺度分割相近的效果,且能够实现不同尺度目标的分割,易于向高维特征扩展,可扩展性强.     

基于PolInSAR三分量分解的建筑物高度向信息提取方法

传统的基于InSAR提取建筑物高程的方法难以区分同一分辨单元内不同散射体的高度信息.文中提出一种基于PolInSAR Freeman三分量分解的城市建筑物高度向信息提取方法,可有效获取同一分辨单元内不同散射体的散射中心.首先对极化干涉互协方差矩阵进行Freeman三分量分解,分离不同散射机制对应的相位中心,然后根据相位信息重建建筑物三维模型.利用覆盖美国加州Richmond地区的两景高分辨率TerraSAR-X极化SAR数据进行实验,结果表明,PolInSAR三分量分解能够分离同一散射单元内不同散射体的相位中心,从而有效提取出建筑物高度向信息及其三维模型.     

基于GIS的南京地籍楼幢数据库设计与实现

指出传统的房屋空间数据和以宗地为基础的楼幢属性数据间的相互孤立、信息联动上的不足,提出以GIS楼幢数据管理为核心,实现"以图管地,以图管房,图、属、档一体化联动"的管理模式,以求为新一代土地登记管理信息系统的建立探索出一条可行之路。     

基于双张影像的城市建筑物高度提取方法

针对现有城市建筑物高度提取方法存在的问题,提出一种基于双张影像的城市建筑物高度简易提取方法。利用高分辨率遥感影像和建筑物立面影像,分别提取样本建筑物的阴影长度和高度,采用最小二乘法解算出影像阴影和建筑物高度的相关公式,通过阴影长度反算出建筑物的高度,从而实现大批量建筑物高度数据的获取。通过建模实例和测量对比实验表明,方法具有操作简单、快速的特点,能满足较高的精度要求,具有一定的应用价值。     

基于MapStar软件在作业应用中的问题探讨

MapStar软件是在数字摄影测量的基础上进行采集、编绘及属性建库;达到了建库与出图并举,基本上实现了生产一体化的作业过程。着重分析了建库数据的质量检查、修改等质量管理工作,为完善MapStar软件提出了建议。     

Results of the ISPRS benchmark on urban object detection and 3D building reconstruction

For more than two decades, many efforts have been made to develop methods for extracting urban objects from data acquired by airborne sensors. In order to make the results of such algorithms more comparable, benchmarking data sets are of paramount importance. Such a data set, consisting of airborne image and laserscanner data, has been made available to the scientific community by ISPRS WGIII/4. Researchers were encouraged to submit their results of urban object detection and 3D building reconstruction, which were evaluated based on reference data. This paper presents the outcomes of the evaluation for building detection, tree detection, and 3D building reconstruction. The results achieved by different methods are compared and analysed to identify promising strategies for automatic urban object extraction from current airborne sensor data, but also common problems of state-of-the-art methods.     

A graph edit dictionary for correcting errors in roof topology graphs reconstructed from point clouds

In the task of 3D building model reconstruction from point clouds we face the problem of recovering a roof topology graph in the presence of noise, small roof faces and low point densities. Errors in roof topology graphs will seriously affect the final modelling results. The aim of this research is to automatically correct these errors. We define the graph correction as a graph-to-graph problem, similar to the spelling correction problem (also called the string-to-string problem). The graph correction is more complex than string correction, as the graphs are 2D while strings are only 1D. We design a strategy based on a dictionary of graph edit operations to automatically identify and correct the errors in the input graph. For each type of error the graph edit dictionary stores a representative erroneous subgraph as well as the corrected version. As an erroneous roof topology graph may contain several errors, a heuristic search is applied to find the optimum sequence of graph edits to correct the errors one by one. The graph edit dictionary can be expanded to include entries needed to cope with errors that were previously not encountered. Experiments show that the dictionary with only fifteen entries already properly corrects one quarter of erroneous graphs in about 4500 buildings, and even half of the erroneous graphs in one test area, achieving as high as a 95% acceptance rate of the reconstructed models.     

Change detection on LOD 2 building models with very high resolution spaceborne stereo imagery

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.     

古建筑测绘成果管理系统设计与实现

本文以古建筑档案管理工作需求为基础,兼顾古建筑展示需要,介绍了基于Flex开发的南通市文保单位及历史建筑管理信息系统。重点介绍了系统的设计原理和具体实现方法。结果表明该系统可较好地管理古建筑测量数据,展示古建筑测绘成果。