Airborne image velocimetry system and its application to measure the surface flow fields of long river reaches
CAO Liekai1, DETERT Martin2,3, LI Danxun1
1. State Key Laboratory of Hydroscience and Engineering, Tsinghua University, Beijing 100084, China; 2. Laboratory of Hydraulics, Hydrology and Glaciology, ETH Zurich, Zurich 8093, Switzerland; 3. Meisser Surveying AG, Chur 7000, Switzerland
Abstract：An airborne image velocimetry (AIV) system is developed for field measurements of long river reaches based on ground control points placed along both riversides and tracking particles seeded onto the water surface. Image frames are taken by an unmanned aerial vehicle in cruise flying mode and stabilized by orthorectification and georeferencing using structure from motion (SfM). Particle image velocimetry is applied to velocity field computation, resulting in a panoramic velocity field. Applications of AIV in urban and rural areas produce high coverage of velocity fields with a high spatial resolution, enabling a detailed description of the flow characteristics. The relative errors of the streamwise velocity components of AIV are ?0% and ?% compared with that of the acoustic Doppler current profiler (ADCP) and flow meter, respectively, which meet the accuracy requirements of field measurements. Overall, with its high reliability and strong applicability, the AIV system could conduct large-scale velocity field measurements with high spatial resolution in long river reaches.
曹列凯, DETERTMartin, 李丹勋. 基于无人机的长河段表面流场测量系统与应用[J]. 清华大学学报（自然科学版）, 2022, 62(12): 1922-1929.
CAO Liekai, DETERT Martin, LI Danxun. Airborne image velocimetry system and its application to measure the surface flow fields of long river reaches. Journal of Tsinghua University(Science and Technology), 2022, 62(12): 1922-1929.
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2022, Vol. 62 
