Urban True Orthophoto Generation and Its Standard Initiative - Phase II

国家数字正射影像计划（NDOP）中数字正射影像生成的早期程序和算法是基于美国地质调查局历史上的制图操作，如野外控制、航空三角测量、四分之一四边形定心、1:40 000航空照片和2.5D数字高程模型，其中一些已经几十年没有更新了。此外，NDOP制定的数字正射影像标准没有考虑大规模城市正射影像生成的要求。与美国地质勘探局的合作项目旨在为不久的将来国家大规模城市数字正射影像部署和国家数字正射影像计划（NDOP）中国家大规模城市数字正射影像标准的修订提供城市大规模数字正射影像创建所需的技术基础（算法、程序等）和经验。该项目将建立在早期的小型NSF资助的基础上，该资助探索了使用现有算法和程序生成真正的正射影像。在这一努力中，现有算法的问题，并研究了解决这些问题的潜在技术。第二阶段（本项目）将进行系统的端到端科学调查，包括：如何规划城市摄影测量飞行任务以最大限度地减少遮挡的影响；如何在生成城市正射影像时有效地表示建筑物（即数字建筑模型- dbm）以检测遮挡和阴影区域；如何从相邻的共轭区域自动（而不是手动）补偿遮挡和阴影区域。如何自动（而不是手动）选择最好的正射影像。如何在真正的正射影像中自动补偿缺失的墙壁信息/数据，以及如何在国家数字正射影像标准化中最好地部署这些技术改进。预计该项目的广泛影响包括：(1)制定修订的国家数字正射影像规范标准，以确保国家测绘计划（NMP）下的大型城市正射影像产品反映当前的测绘和数据政策，并且在风格和内容上准确一致。(2)将成为大规模城市数字真正射影像用户的各级政府。地理信息系统技术的最新进展促进了将数字正射影像与越来越多的其他地理空间数据整合到无数应用中。美国地质调查局正射影像的传统用户，如联邦土地和资源管理机构，将是主要用户。(3)真正的正射影像生成技术的进步将被转移到美国工业界，以促进这些公司在全球GIS市场上的竞争力。ESRI公司作为合作者加入了第二阶段，并将能够直接使用项目成果。(4)开发的程序和算法以及第一手的研究成果将直接和立即输入到Old Dominion University和其他学术机构的摄影测量学和GIS课程中。创建的实验数据集，包括原始图像、正射影像、DEM、城市空间数据、三维城市模型等，将直接用于摄影测量学和GIS实验课。

Early procedures and algorithms for digital orthophoto generation in the National Digital Orthophoto Program (NDOP) were based on historic US Geological Survey mapping operations, such as field control,aerotriangulation, the quarter-quadrangle-centering, 1:40,000 aerial photographs, and 2.5D digitalelevation models, some of which have not been updated in decades. Additionally, the Standard for Digital Orthophoto formulated by the NDOP has not considered the requirements of large-scale urban orthophoto generation. This collaborative project with USGS is intended to provide the technical base (algorithms, procedures, etc.) and experience needed for urban large-scale digital orthophoto creation for the near future national large-scale urban digital orthophoto deployment and the revision of the Standards for National Large-scale City Digital Orthophoto in the National Digital Orthophoto Program (NDOP). The project will build on an earlier small NSF grant which explored true orthophoto generation using existing algorithms and procedures. In that effort, the problems of the existing algorithms, and investigated potential techniques for solving them were identified. Phase II, (this project) will conduct a systematic, end-to-end scientific investigation, including:o How to plan urban photogrammetric flying missions to minimize the impact of occlusion,o How to effectively represent buildings (i.e., digital building model-DBM) for the detection of theoccluded and shadow areas when generating urban orthophotos,o How to automatically (NOT manually) compensate for the occluded and shadowed areas fromconjugate areas in adjacent .slave. orthophotos,o How to automatically (NOT manually) choose the .best. imagery and optimal seam lines whenrefilling the occluded areas,o How to automatically compensate for the missed wall information/data in true orthophoto, ando How to best deploy these technical improvements within the National Digital Orthophoto Standardinitiative.The broad impacts from this project are expected to include: (1) Develoopment of revised National Standards for Digital Orthophoto specifications to ensure that large-scale urban orthophoto products under the National Mapping Program (NMP) reflect current mapping and data policies and are accurate and consistent in style and content.(2) All levels of government who will be users of large-scale urban digital true orthophotos. Recent advances in GIS technology have facilitated the integration of digital orthophotos, with an increasing variety of other geospatial data, into myriad applications. Traditional users of USGS orthophotos, like federal land and resource management agencies, will be principal users. (3) Advances in true orthophoto generation that will be transferred to American industry to contribute to the competitiveness of these companies in the global GIS marketplace. ESRI Inc. joins this Phase II as a collaboratork and will be in a position to make direct use of project results.(4) The developed procedures and algorithms, and the firsthand research results will be directly and immediately fed into photogrammetry and GIS courses at Old Dominion University and other academic institutions. The created experimental data sets,including original images, orthorectified images, DEM, urban spatial data, 3D urban model, etc., will be directly used in laboratory classes of photogrammetry and GIS.