摘要:
针对消费级无人机相机单一、镜头畸变大,地形建模精度受航线设计和控制测量的影响等问题,设计了不同的数据采集方案和控制点蒙特卡罗检验,分析了相机倾角、航高和控制点数量对地形建模精度的影响。在黄土高原3个典型小流域的实验结果表明: ①在进行无人机摄影测量数据处理时,应先使用蒙特卡罗检验对控制点质量进行分析,排除控制点误差再进行数据处理。②相机倾角方面,在无地面控制点时,采用较大角度的倾斜摄影不仅有利于提高样区整体精度,还优化了误差的空间分布; 这与相机畸变模型的优化有关。在有地面控制点时,相机倾角对高程精度的影响不大,但是影响控制点饱和数量; 相对于垂直摄影,倾斜摄影需要略多的控制点才能达到最优精度。③航高方面,在有地面控制点时,使用倾斜摄影有利于降低高程精度对航高变化的敏感性。在有地面控制点时,航高在60~160 m范围内对高程精度的影响不明显,且航高变化不影响控制点饱和数量。
Abstract:
Consumer-grade unmanned aerial vehicles (UAVs) each have a single camera and high lens distortion. The accuracy of terrain modeling using UAVs is influenced by route design and control surveys. By designing different data collection schemes and Monte Carlo tests, this study investigated the influence of the camera’s tilt angle, flight height, and the number of ground control points (GCPs) on terrain modeling accuracy in three small river basins on the Loess Plateau. The results are as follows: ① Before the processing of UAV photogrammetry data, it is necessary to analyze the quality of GCPs through Monte Carlo tests to eliminate GCP errors. ② The effects of the tilt angles of cameras include: in the case of no available GCPs, tilt photogrammetry with tilt angles of cameras can both improve the overall accuracy of the sampling area and optimize the spatial distribution of errors, with these advantages related to the optimization of the camera distortion model; in the case of available GCPs, the camera tilt angle has minor influence on elevation accuracy but affects the saturation number of GCPs. Compared with vertical photogrammetry, tilt photogrammetry requires slightly more GCPs to achieve the optimal accuracy. ③ The effects of the flight height include: in the case of no available GCPs, tilt photogrammetry can reduce the sensitivity of elevation accuracy to flight height; in the case of available GCPs, flight heights of 60~160 m have no significant influence on elevation accuracy, and the change in flight height does not affect the saturation number of GCPs.
下载: