从机载激光扫描数据中交互式提取人字形房屋模型的方法研究

快速有效地从机载激光扫描(airborne lidar)点云数据中提取房屋模型是机载激光扫描系统应用研究的一项重要课题。鉴于交互式半自动方法是从点云数据中提取简单规则房屋模型信息的一种可行的方法,为此采用3维空间中改进的Hough变换以及聚类分析,提出了一种从点云数据中交互式提取人字形房屋模型的方法。该方法分为3个步骤:第1步是用户确定房屋区域,并分割出候选的屋顶点集;第2步是对候选屋顶点集采用3维空间中改进的Hough变换,然后对Hough变换后所获得的参数集进行聚类分析,以此获得屋顶所在平面的参数表达;第3步是构造完整的房屋模型。通过屋顶平面相交得到屋脊线,通过点的范围分析确定屋顶的边缘,最后添加竖直的墙面构造完整的房屋模型。经采用Optech公司提供的数据进行实验初步证实,该方法是可行的,且整个提取过程只需要很少的用户交互,因此适合于大规模处理机载激光扫描数据。

Approach on Interactive Extraction of Gable-roofed Building Models from Airborne Lidar Data

Fast and efficient extraction of building models from airborne lidar data is an important research topic in applications of airborne lidar system.The semi-automatic method with user's interaction is a practicable approach for extracting simple and regular buildings from point cloud data.Based on this view,a method of interactively extracting gable-roofed building models from lidar point cloud data is proposed in this paper.An improved Hough transformation in 3D space and Cluster Analysis Model are key points of this approach.The proposed method consists of three steps.First,the user roughly input a region where a building is located.The candidate points belonging to the building roof are then filtered out.Second,an improved Hough transformation in 3D space and Cluster Analysis Model are applied to the data set of roof points to acquire parametric expressions of roof planes.The third step is to construct the integrated building model.The roof's ridge line is obtained by intersecting roof planes,and the building's footprint is determined by analysis of roof points.Finally,a complete building model is created by adding vertical walls.Tested with sample lidar data from Optech Company,this approach gets good experimental results with very few user interactions needed.