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

Casella, Elisa; Collin, Antoine; Harris, David; Ferse, Sebastian C. A.; Bejarano, Sonia; Parravicini, Valeriano; Hench, James L.

doi:10.1007/s00338-016-1522-0

Cited by 230 publications

(212 citation statements)

References 25 publications

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“…It would also be useful to explore how model quality is affected by water conditions, available lighting (quality/quantity), depth, and other environmental factors ( e.g., [57] look at sun and wind patterns to find the optimum daytime for filming).…”

Section: Resultsmentioning

confidence: 99%

Cost and time-effective method for multi-scale measures of rugosity, fractal dimension, and vector dispersion from coral reef 3D models

et al. 2017

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We present a method to construct and analyse 3D models of underwater scenes using a single cost-effective camera on a standard laptop with (a) free or low-cost software, (b) no computer programming ability, and (c) minimal man hours for both filming and analysis. This study focuses on four key structural complexity metrics: point-to-point distances, linear rugosity (R), fractal dimension (D), and vector dispersion (1/k). We present the first assessment of accuracy and precision of structure-from-motion (SfM) 3D models from an uncalibrated GoPro™ camera at a small scale (4 m2) and show that they can provide meaningful, ecologically relevant results. Models had root mean square errors of 1.48 cm in X-Y and 1.35 in Z, and accuracies of 86.8% (R), 99.6% (D at scales 30–60 cm), 93.6% (D at scales 1–5 cm), and 86.9 (1/k). Values of R were compared to in-situ chain-and-tape measurements, while values of D and 1/k were compared with ground truths from 3D printed objects modelled underwater. All metrics varied less than 3% between independently rendered models. We thereby improve and rigorously validate a tool for ecologists to non-invasively quantify coral reef structural complexity with a variety of multi-scale metrics.

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Section: Resultsmentioning

confidence: 99%

Cost and time-effective method for multi-scale measures of rugosity, fractal dimension, and vector dispersion from coral reef 3D models

et al. 2017

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“…These level, very shallow reef flats are ideal locations for sUAS surveys. During low-wind periods, Kāne'ohe Bay can experience very calm sea states and good visibility that are optimal for the successful use of sUAS surveys (Casella et al 2016). During the Summer/ Fall months of 2015, high atmospheric and ocean temperatures coincided with low winds to push nearshore temperatures above 30°C, leading to extensive coral bleaching throughout Kāne'ohe Bay (R Ritson-Williams, K Bahr pers.…”

Section: Study Sitementioning

confidence: 99%

“…UASderived spatial data can be used in conjunction with traditional remote sensing techniques and in situ methods to understand coral species and morphology assemblages that may indicate cyclical stress events, identify suitable fish habitat and by association potential suitable sites for Marine Protected Areas (MPAs), quantify the spatial complexity of fine-scale shallow water depositional systems and map other indicators such as disease, physical impacts and macroalgae cover that increase our understanding of coral reef resilience (Purkis and Riegl 2005;Purkis et al 2008Purkis et al , 2017Rowlands et al 2012;Knudby et al 2013;Casella et al 2016).…”

Section: Future Studiesmentioning

confidence: 99%

Assessing the spatial distribution of coral bleaching using small unmanned aerial systems

Levy

Hunter

Lukacazyk³

et al. 2018

Coral Reefs

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Small unmanned aerial systems (sUAS) are an affordable, effective complement to existing coral reef monitoring and assessment tools. sUAS provide repeatable low-altitude, high-resolution photogrammetry to address fundamental questions of spatial ecology and community dynamics for shallow coral reef ecosystems. Here, we qualitatively describe the use of sUAS to survey the spatial characteristics of coral cover and the distribution of coral bleaching across patch reefs in Kāne'ohe Bay, Hawaii, and address limitations and anticipated technology advancements within the field of UAS. Overlapping subdecimeter low-altitude aerial reef imagery collected during the 2015 coral bleaching event was used to construct highresolution reef image mosaics of coral bleaching responses on four Kāne'ohe Bay patch reefs, totaling 60,000 m 2 . Using sUAS imagery, we determined that paled, bleached and healthy corals on all four reefs were spatially clustered. Comparative analyses of data from sUAS imagery and in situ diver surveys found as much as 14% difference in coral cover values between survey methods, depending on the size of the reef and area surveyed. When comparing the abundance of unhealthy coral (paled and bleached) between sUAS and in situ diver surveys, we found differences in cover from 1 to 49%, depending on the depth of in situ surveys, the percent of reef area covered with sUAS surveys and patchiness of the bleaching response. This study demonstrates the effective use of sUAS surveys for assessing the spatial dynamics of coral bleaching at colonyscale resolutions across entire patch reefs and evaluates the complementarity of data from both sUAS and in situ diver surveys to more accurately characterize the spatial ecology of coral communities on reef flats and slopes.

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“…3. Hardy et al (2017) Mapping malaria vector habitats Pulver et al (2016) Transporting automated external defibrillators Chabot and Francis (2016) Bird detection Hodgson et al (2017) Surveying marine fauna Sankey et al (2017) Forest monitoring Casella et al (2017) Mapping coral reefs Szantol et al (2017) Mapping orangutan habitat Chowdhury et al (2017) Disaster response and relief Restas (2015) Supporting disaster management (earthquakes, floods, fires) Source Own elaboration from different sources …”

Section: Us$) Sourcementioning

confidence: 99%

The Drone Sector in Europe

Molina¹,

Oña²

2017

SpringerBriefs in Law

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The aim of this chapter is to review the industry sector in Europe, which involves big companies as well as SMEs. The leading European countries, the main competitors, and the main competitive advantages of the industry are analysed. We have identified five different segments in which companies compete based on distinctive features (toys, hobby/leisure, professional, commercial, and military). The homogenization of the industry, especially in the toy, hobby, and commercial subsectors, is mainly led by big companies, which at the same time also represent the largest market share. We have concluded that there are no entry barriers besides technology and commercial distribution, but the main difficulty that is hampering the industry's expansion is regulation. This affects in particular the hobby/leisure and commercial drone segments, some areas more than others; while agricultural and military drones are expanding and evolving rapidly, professional filming and photography and toys are still too dependent on safety or legal issues, such as privacy concerns. It is also remarkable that companies from China and the USA are reaching the top positions. This should be taken into consideration by European policy makers, as the decisions made in the next years will be the key to the development of the sector in Europe.

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

Cited by 230 publications

References 25 publications

Cost and time-effective method for multi-scale measures of rugosity, fractal dimension, and vector dispersion from coral reef 3D models

Cost and time-effective method for multi-scale measures of rugosity, fractal dimension, and vector dispersion from coral reef 3D models

Assessing the spatial distribution of coral bleaching using small unmanned aerial systems

The Drone Sector in Europe

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