基于Agisoft PhotoScan 的无人机影像自动拼接在风景园林规划中的应用

【目的】通过构建研究区三维可视化直观模型,为大尺度风景园林规划设计提供前期分析资料。【方法】以南京神策门公园为研究区,通过轻小型无人机低空航测方式获取原始数据,利用Agisoft PhotoScan程序进行数据处理,自动对齐输入影像并进行优化处理,定向提取密集点云,建立不规则三角网(TIN)及数字正射影像(DOM)的制作。 根据生成的三维可视化直观模型建立研究区域完整的正射影像,同时结合ArcGIS和ENVI等软件进行空间信息量化分析。【结果】无人机观测值与GPS观测值对比拟合得到线性回归模型,二者相关系数R=0.994; 将输出的正射影像在ArcGIS中进行空间分析得到神策门公园绿地面积为36 974.78 m²,在ENVI中进行监督分类得到研究区土地利用类型统计表,其中绿地占比为64.34%。【结论】Agisoft PhotoScan软件在处理无人机影像时自动拼接精度较高,拼接影像时效性较好; 对于较大尺度范围,能够有效提取风景园林规划设计前期分析所需的场地地理信息,并实现信息的量化分析。

Application of unmanned aerial vehicle(UAV)image automatic stitching in landscape planning based on Agisoft PhotoScan

Abstract: 【Objective】Based on the developing trends of landscape architecture planning, this paper presents a three-dimensional visualization model for the study area to provide pre-analysis data for the planning and design of large-scale landscape architecture. 【Method】Nanjing Shence Gate Park was selected as the research site, and the primary data were acquired using a small unmanned aerial vehicle(UAV)via measurement of low latitude. The Agisoft PhotoScan software could be used for data processing, including the alignment and optimization of an input image, the orientation extraction of a dense point cloud, and the establishment of a triangulated irregular network(TIN)and a digital ortho image map(DOM). The complete DOM of the research area could then be established based on the three-dimensional visualization model. The ArcGIS and ENVI softwares could be used alongside this for quantitative spatial information analysis.【Result】The correlation coefficient between the observed global positioning system(GPS)value and the UAV, which, as determined using the linear regression equation, is high at R=0.994. According to the spatial analysis conducted using ArcGIS, the green area in Shence Gate Park covered 36 974.78 m². The table of land use types in the study area was obtained through the supervised classification(maximum likelihood classification)conducted using ENVI, and the research area was divided into four different land use types: water, green land, buildings and roads, and the green land rate was 64.34%.【Conclusion】The Agisoft PhotoScan software could automatically stitch UAV images with high precision. The stitched image had the advantage of timeliness and exhibits a large scale range, which could effectively create a mosaic of multi-UAV images and extract the geographical information of the site required for pre-analysis during landscape planning and design, and allowed the information to be quantitatively analyzed.