Measuring gullies by synergetic application of UAV and close range photogrammetry - A case study from Andalusia, Spain
Measuring gullies by synergetic application of UAV and close range photogrammetry - A case study from Andalusia, Spain
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DOI：
10.1016/j.catena.2015.04.004
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发表时间：
2015-09-01
期刊：
影响因子：
6.2
通讯作者：
Karrasch, Pierre
中科院分区：
文献类型：
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作者：
Stoecker, Claudia;Eltner, Anette;Karrasch, Pierre
沟壑自然地表现出复杂的形态，因此难以测量。摄影测量方法是很有前途的工具，可以在不干扰表面的情况下从重叠图像中进行 3D 重建，从而克服此类问题。机载（例如无人机）和地面图像采集平台是全面数字沟壑建模的可能数据源。在本研究中，介绍了一种协同利用无人机和地面图像来生成高分辨率 3D 模型的方法。虽然需要适当的无人机任务规划，但可以根据遇到的地形条件自发灵活地获取地面图像来补充无人机数据。在不限制精度要求的情况下，地面图像仅使用来自现有 3D 模型的附加信息和来自无人机图像处理的正射影像进行处理。在此野外活动中，无人机适合灵活、频繁的沟壑监测。然而，根据具体情况的飞行配置，由于鸟瞰视野有限，3D 建模仅限于陡峭的沟壑壁（坡度大于 50-60 度）以及悬垂的沟壑壁。额外的地面图像用于克服这些限制并填补数据空白。在这项研究中，最终的合并数字沟渠模型显示分辨率约为 0.5 厘米，精度为 1 厘米。对安达卢西亚（西班牙）的沟壑头进行了分析，以确认协同数据利用的适用性。研究了冬季三个月的研究期，以测量多时相 3D 体积变化。对于 170 m(2) 的沟渠面积，正体积平衡达到 5 m(3)，主要是由人为相互作用造成的。总之，无人机和地面数据的结合可以实现频繁间隔的具有高空间分辨率的综合沟壑模型。 (C) 2015 Elsevier B.V. 保留所有权利。
Gullies naturally exhibit complex morphologies and hence are difficult to measure. Photogrammetric methods are promising tools to overcome such problems due to 3D reconstruction from overlapping images without disturbing the surface. Airborne (e.g. unmanned aerial vehicles, UAV) and terrestrial image acquisition platforms are possible data sources for comprehensive digital gully modelling. In this study, an approach for the synergetic utilisation of UAV and terrestrial images for high resolution 3D model generation is introduced. While proper UAV mission planning is necessary, terrestrial images can be acquired spontaneously and flexibly depending on the encountered terrain conditions to supplement UAV data. Without confining accuracy demands, terrestrial images are processed solely with additional information from already existent 3D models and orthophotos from UAV image processing. During this field campaign UAVs are suitable for flexible and frequent gully monitoring. However, with the case specific flight configuration, 3D modelling is restricted at steep gully walls - above slope gradients of 50-60 degrees - as well as overhanging gully walls, due to the limiting birds-eye view. Additional terrestrial images are used to overcome these limitations and fill up data gaps. In this study the final merged digital gully model reveals a resolution about 0.5 cm and an accuracy of 1 cm. A gully headcut in Andalusia (Spain) is analysed to confirm the suitability of the synergetic data utilisation. A study period of three months during winter season is investigated to measure multi-temporal 3D volume changes. The positive volume balance amounts to 5 m(3) for a gully area of 170 m(2) and is caused mainly by anthropogenic interactions. Concluding, the combination of UAV and terrestrial data allow for comprehensive gully models with high spatial resolution at frequent intervals. (C) 2015 Elsevier B.V. All rights reserved.