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Istenič, Klemen; Gracias, Nuno; Arnaubec, Aurelien; Escartín, Javier; Garcia, Rafael. |
Improvements in structure-from-motion techniques are enabling many scientific fields to benefit from the routine creation of detailed 3D models. However, for a large number of applications, only a single camera is available for the image acquisition, due to cost or space constraints in the survey platforms. Monocular structure-from-motion raises the issue of properly estimating the scale of the 3D models, in order to later use those models for metrology. The scale can be determined from the presence of visible objects of known dimensions, or from information on the magnitude of the camera motion provided by other sensors, such as GPS. This paper addresses the problem of accurately scaling 3D models created from monocular cameras in GPS-denied environments,... |
Tipo: Text |
Palavras-chave: Structure-from-motion; Underwater 3D reconstruction; Photogrammetry; Laser scalers. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00591/70338/68394.pdf |
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Girard, Fanny; Sarrazin, Jozee; Arnaubec, Aurelien; Cannat, Mathilde; Sarradin, Pierre-marie; Wheeler, Benjamin; Matabos, Marjolaine. |
The deep sea is characterized by a wide range of landscapes, including complex features where topography and currents interact to form highly heterogeneous habitats. In addition to a complex topography, hydrothermal vent environments are characterized by strong environmental gradients that structure the spatial distribution of biological communities. The role of vent fluid temperature and chemical composition on species distribution is now well understood, but investigations on the effects of the complex sulfide edifice topography are scarce. Here, we used a novel approach combining 3D photogrammetric reconstruction, in situ environmental measurements and modeling to characterize assemblage distribution on the active edifice Eiffel Tower (Lucky Strike,... |
Tipo: Text |
Palavras-chave: Mid-Atlantic Ridge; Eiffel Tower; EMSO-Azores; Ecology; Imagery; 3D photogrammetry; Deep-sea observatories; Topographic effects. |
Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00640/75211/75349.pdf |
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Fabri, Marie-claire; Vinha, Beatriz; Allais, Anne-gaelle; Bouhier, Marie-edith; Dugornay, Olivier; Gaillot, Arnaud; Arnaubec, Aurelien. |
Cold-water coral ecosystems have been identified as vulnerable, but quantitative data on their conservation status is very limited. The Marine Strategy Framework Directive (MSFD) is the tool implemented by the European Union’s Integrated Maritime Policy to achieve Good Environmental Status (GES) of marine waters by 2020. In this context, the aim of this study was to evaluate the Ecological Status of benthic habitats in Cassidaigne canyon, focusing in particular on cold-water coral habitats dominated by Madrepora oculata. Data were collected during the Videocor1 cruise (2017). Videos and photos collected during eight dives of the H-ROV Ariane were used to reconstruct, in 3-dimensions, the areas where cnidarians have settled in the canyon. A total of 33 3D... |
Tipo: Text |
Palavras-chave: Biodiversity; Photogrammetry; Habitat mapping; Bauxite residues; Vulnerable marine ecosystems. |
Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00511/62293/66719.pdf |
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Sen, Arunima; Dennielou, Bernard; Tourolle, Julie; Arnaubec, Aurelien; Rabouille, Christophe; Olu, Karine. |
This study characterizes the habitats and megafaunal community of the Congo distal lobe complex driven by turbidity currents through the use of remotely operated vehicle (ROV) still imagery transects covering distances in the order of kilometers. In this sedimentary, abyssal area about 5000 m deep and 750 km offshore from western Africa, large quantities of deposited organic material supplied by the Congo River canyon and channel support aggregations of large sized foraminifers (Bathysiphon sp.) and vesicomyid clams (Christineconcha regab, Abyssogena southwardae) often associated with methane cold seeps, as well as opportunistic deep-sea scavengers. Additionally, bacterial mats, assumed to be formed by large sulfur-oxidizing filamentous bacteria (Beggiatoa... |
Tipo: Text |
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Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00385/49614/50126.pdf |
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Lim, Aaron; Wheeler, Andrew J.; Arnaubec, Aurelien. |
Framework-forming cold-water corals (CWC's) such as Lophelia pertusa and Madrepora oculata generate positive topographic features on the seabed called CWC mounds. In the North East Atlantic, CWC mounds have been studied in detail and reveal heterogeneous spatial on-mound organisation of coral patches. Many of these studies are limited by a paucity of remotely-sensed and video imagery at an appropriate resolution and coverage. This study is the first attempt to video mosaic an entire CWC mound (the Piddington Mound of the Moira Mounds, Porcupine Seabight, Irish margin). The mosaic is divided into 18,980 0.25 m2 cells with a manual classification applied to each within a geographic information system (GIS). Geospatial analysis shows that cell distribution is... |
Tipo: Text |
Palavras-chave: Cold-water coral; Habitat mapping; Spatial analysis; Sediments; Fades distribution. |
Ano: 2017 |
URL: http://archimer.ifremer.fr/doc/00390/50129/50732.pdf |
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Lim, Aaron; Kane, Adam; Arnaubec, Aurelien; Wheeler, Andrew J.. |
Cold-water coral (CWC) habitats are commonly regarded as hotspots of biodiversity in the deep-sea. However, a standardised approach to monitoring the effects of climate change, anthropogenic impact and natural variability through video-surveying on these habitats is poorly-established. This study is the first attempt at standardising a cost-effective video-survey design specific to small CWC mounds in order to accurately determine the proportion of facies across their surface. The Piddington Mound of the Moira Mounds, Porcupine Seabight, offshore Ireland has been entirely imaged by downward-facing video in 2011 and 2015. The 2011 video data is navigated into a full-mound, georeferenced video mosaic. A quadrat-based manual classification of this video... |
Tipo: Text |
Palavras-chave: Cold water corals; Mounds; Video survey design; Sediments; Habitat mapping. |
Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00403/51482/53728.pdf |
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