Mapping coral reefs using consumer-grade drones and structure from motion photogrammetry techniques

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• 作者：Elisa Casella ; Antoine Collin ; Daniel Harris ; Sebastian Ferse…
• 关键词：Drone mapping ; Coral reefs ; Bathymetry from drones ; Structure from motion underwater ; Bathymetry from photogrammetry
• 刊名：Coral Reefs
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：36
• 期：1
• 页码：269-275
• 全文大小：
• 刊物类别：Earth and Environmental Science
• 刊物主题：Freshwater & Marine Ecology; Oceanography;
• 出版者：Springer Berlin Heidelberg
• ISSN：1432-0975
• 卷排序：36

文摘

We propose a novel technique to measure the small-scale three-dimensional features of a shallow-water coral reef using a small drone equipped with a consumer-grade camera, a handheld GPS and structure from motion (SfM) algorithms. We used a GoPro HERO4 with a modified lens mounted on a DJI Phantom 2 drone (maximum total take-off weight <2 kg) to perform a 10 min flight and collect 306 aerial images with an overlap equal or greater than 90%. We mapped an area of 8380 m2, obtaining as output an ortho-rectified aerial photomosaic and a bathymetric digital elevation model (DEM) with a resolution of 0.78 and 1.56 cm pixel−1, respectively. Through comparison with airborne LiDAR data for the same area, we verified that the location of the ortho-rectified aerial photomosaic is accurate within ~1.4 m. The bathymetric difference between our DEM and the LiDAR dataset is −0.016 ± 0.45 m (1σ). Our results show that it is possible, in conditions of calm waters, low winds and minimal sun glint, to deploy consumer-grade drones as a relatively low-cost and rapid survey technique to produce multispectral and bathymetric data on shallow-water coral reefs. We discuss the utility of such data to monitor temporal changes in topographic complexity of reefs and associated biological processes.