STEREO RECONSTRUCTION OF SURF ZONE WAVES USING UAV

To understand complex nearshore processes, detailed in situ wave observations are indispensable. This paper presents a new measurement method for surf zone waves based on stereo three-dimensional reconstruction with UAVs (Unmanned Aerial Vehicles). In this method, surf zone waves were filmed by two UAVs hovered at different positions, and the relative camera pose was computed with SURF (Speeded Up Robust Feature) for each pair of corresponding stereo video frames. Then, disparity was estimated by semi-global block matching, and the three-dimensional structure of water surface in the world coordinate was constructed using ground control points deployed on the beach. The temporal-spatial changes of estimated water surface represent longshore variation of wave height behind detached breakwaters, and the results agreed roughly with measured water level by a wave gauge.