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| Fezzani, Ridha; Berger, Laurent. |
| An automated signal-based method was developed in order to analyse the seafloor backscatter data logged by calibrated multibeam echosounder. The processing consists first in the clustering of each survey sub-area into a small number of homogeneous sediment types, based on the backscatter average level at one or several incidence angles. Second, it uses their local average angular response to extract discriminant descriptors, obtained by fitting the field data to the Generic Seafloor Acoustic Backscatter parametric model. Third, the descriptors are used for seafloor type classification. The method was tested on the multi-year data recorded by a calibrated 90-kHz Simrad ME70 multibeam sonar operated in the Bay of Biscay, France and Celtic Sea, Ireland. It... |
| Tipo: Text |
Palavras-chave: Multibeam; Reflectivity; Backscatter angular response; Segmentation. |
| Ano: 2018 |
URL: https://archimer.ifremer.fr/doc/00423/53465/56648.pdf |
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| Sen, Arunima; Ondreas, Helene; Gaillot, Arnaud; Marcon, Yann; Augustin, Jean-marie; Olu, Karine. |
| Deep-sea ecosystems have attracted considerable commercial interest in recent years because of their potential to sustain a diverse range of mankind's industrial needs. If these systems are to be preserved or exploited in a sustainable manner, mapping habitats and species distributions is critical. As biodiversity at cold-seeps or other deep-sea ecosystems is driven by habitat heterogeneity, imagery is the obvious choice for characterizing these systems and has indeed proven extremely valuable towards mapping biogenic habitats formed by dense aggregations of large sized species, such as coral reefs, tubeworm bushes or bivalve beds. However, the acquisition of detailed images with resolution sufficient for reliable identification is extremely time... |
| Tipo: Text |
Palavras-chave: Mapping; Cold seeps; Multibeam; Bathymetry; Backscatter; Biogenic habitats. |
| Ano: 2016 |
URL: http://archimer.ifremer.fr/doc/00312/42286/41612.pdf |
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| Okay, Seda; Jupinet, Benoit; Lericolais, Gilles; Cifci, Gunay; Morigi, Catherina. |
| In 2002, the Bosphorus outlet was mapped using an EM 300 multibeam echo-sounder together with a Chirp sonar system. This survey, carried out on board the Ifremer RV 'Le Suroit' in the frame of the BlaSON project, completes the data previously acquired directly at the mouth of the Bosphorus by Di Iorio et al. (1999) in the frame of a NATO SACLANT Undersea Research project using jointly the NATO RV Alliance, and the Turkish Navy Survey ship 'Cubuklu'. This acoustic imaging has identified a canyon system at the slope and a shallow marine fan, which contains shelf incisions extending the Istanbul Strait incision. Multibeam bathymetry, ultra-high resolution seismic profiling and coring correlations on this subaqueous fan area allowed reconstruction of... |
| Tipo: Text |
Palavras-chave: Multibeam; High resolution seismic; Sea level change; High energy Mediterranean water input; Subaqueous fan. |
| Ano: 2011 |
URL: http://archimer.ifremer.fr/doc/00036/14676/13677.pdf |
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| Le Bouffant, Naig; Berger, Laurent; Lurton, Xavier. |
| Bathymetric multibeam echosounders (MBES) classically improve their bottom detection resolution by increasing the number of beams with narrower beamwidths. Many independent detections are thus obtained when extracting one sounding in each beam. However when the pulse footprint on the bottom gets narrower than the beamwidth, which often happens at high incidence angles, it is possible to extract several independent bottom detections within the same beam. These high-density soundings extraction methods present a still higher interest for MBES designed with rather “wide” beams (say 3° or more), so as to offer other benefits, such as compacity, low-cost, or low sidelobe levels as for fishery applications. This paper presents a simple way to derive multiple... |
| Tipo: Text |
Palavras-chave: Multibeam; Bathymetry; Interferometry; Beamwidth. |
| Ano: 2013 |
URL: http://archimer.ifremer.fr/doc/00146/25719/23801.pdf |
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| Montereale-gavazzi, Giacomo; Roche, Marc; Lurton, Xavier; Degrendele, Koen; Terseleer, Nathan; Van Lancker, Vera. |
| To characterize seafloor substrate type, seabed mapping and particularly multibeam echosounding are increasingly used. Yet, the utilisation of repetitive MBES-borne backscatter surveys to monitor the environmental status of the seafloor remains limited. Often methodological frameworks are missing, and should comprise of a suite of change detection procedures, similarly to those developed in the terrestrial sciences. In this study, pre-, ensemble and post-classification approaches were tested on an eight km2 study site within a Habitat Directive Area in the Belgian part of the North Sea. In this area, gravel beds with epifaunal assemblages were observed. Flourishing of the fauna is constrained by overtopping with sand or increased turbidity levels, which... |
| Tipo: Text |
Palavras-chave: Multibeam; Seafloor backscatter; Change detection; Seafloor integrity; Marine Strategy Framework Directive; Reference calibration area. |
| Ano: 2018 |
URL: http://archimer.ifremer.fr/doc/00387/49807/50379.pdf |
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