由航空影像自动重建大范围3维地形

Automatic reconstruction of large area 3D terrain from aerial imagery

目的针对由航空影像自动生成大范围3维地形的立体模型配准问题,提出一种自动配准全部立体模型的方法,从而生成大范围3维地形。方法首先由相邻影像构建独立的立体模型;然后根据特征匹配同名点在公共影像上的坐标对应关系,自动提取相邻模型的连接点;通过循环遍历搜索,自动配准全部立体模型,进而构建全航摄区的大范围3维地形。结果采用两组数据进行实验,结果显示,两组数据全部3维模型的均方配准误差分别为5.20像素和2.63像素。本文方法生成的大范围地形的相对精度较高;对第2组数据的结果采用控制点进行绝对定向,并用检查点进行精度评估,结果显示全部检查点的均方平面和高程误差分别为0.326 m和0.502 m,生成的大范围地形达到了较高的绝对精度。结论本文方法可自动化执行,仅需输入一系列有一定重叠的航空影像,即可自动生成按一定方式组织的大范围3维地形产品。该方法生成的大范围地形既可用于3维场景浏览,也可用于地形量测,但不适用于由激光扫描获取的点云数据的配准。

Objective Considering the stereo model registration in large-scale 3 D terrain reconstruction from aerial imagery,we propose an approach for registering all stereo models to realize automatic large-scale 3D terrain reconstruction.Individual stereo models were constructed from the adjacent images.Method The tie points of adjacent models were extracted according to the pixel coordinates of the corresponding points based on feature matching in the shared image.All models were linked and registered through loop traversal search.Subsequently,the large area terrain of the overall aerial photography area was produced through triangulation,Tin generation,differential correction,elevation interpolation,and color blending.The above processes were sequentially and automatically performed.Result Two groups of data were applied in the experiment.Results showed that the root-mean-square （RMS） registration errors of all 3D models of the two data sets were 5.20 and 2.63 pixels.The relative accuracy of the produced large-scale terrain was high.The absolute orientation was determined based on the results generated from the second data set with ground control points,and the absolute positioning accuracy was evaluated using checkpoints.The RMS errors of the check points in the planimetry and altitude were 0.326 and 0.502 m,respectively,illustrating a high absolute accuracy.Couclusion Large-scale 3D terrain that was organized in a special format was automatically produced by incorporating a series of overlapped aerial imagery.The visualized and realistic 3D terrain validated the feasibility and effectiveness of the proposed solution.