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Coherent heat patterns revealed by unsupervised classification of Argo temperature profiles in the North Atlantic Ocean ArchiMer
Maze, Guillaume; Mercier, Herle; Fablet, Ronan; Tandeo, Pierre; Radcenco, Manuel Lopez; Lenca, Philippe; Feucher, Charlene; Le Goff, Clement.
A quantitative understanding of the integrated ocean heat content depends on our ability to determine how heat is distributed in the ocean and what are the associated coherent patterns. This study demonstrates how this can be achieved using unsupervised classification of Argo temperature profiles. The classification method used is a Gaussian Mixture Model (GMM) that decomposes the Probability Density Function of a dataset into a weighted sum of Gaussian modes. It is determined that the North Atlantic Argo dataset of temperature profiles con- tains 8 groups of vertically coherent heat patterns, or classes. Each of the temperature profile classes reveals unique and physically coherent heat distributions along the vertical axis. A key result of this study is...
Tipo: Text Palavras-chave: Heat content; Classification North Atlantic; Stratification; Water mass; Thermocline; Argo; Pattern.
Ano: 2017 URL: http://archimer.ifremer.fr/doc/00363/47431/47456.pdf
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Reconstructing individual shape histories of fish otoliths: A new image-based tool for otolith growth analysis and modeling ArchiMer
Fablet, Ronan; Chessel, Anatole; Carbini, Sebastien; Benzinou, Abdesslam; De Pontual, Helene.
In this paper is presented a novel image processing tool for the extraction of geometric information in otolith images. It relies on the reconstruction of individual otolith shape histories from otolith images. Based on the proposed non-parametric level-set representation of otolith shape history, applications to the extraction of growth axes and ring structures in otolith images are first considered. A second category of applications concern the analysis of 2D otolith growth. The potential of the proposed framework is illustrated on real otolith images for various species (e.g., cod, pollock) and discussed with a particular emphasis on the genericity of the approach and on applications such as otolith shape analysis, multi-proxy otolith analysis, otolith...
Tipo: Text Palavras-chave: 2D otolith growth; Growth axis extraction; Growth ring extraction; Shape dynamics; Otolith imaging.
Ano: 2009 URL: http://archimer.ifremer.fr/doc/2009/publication-6319.pdf
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Des otolithes aux satellites: méthodes et applications du traitement du signal et des images pour l'observation de l'océan ArchiMer
Fablet, Ronan.
This document presents a synthesis of my research activities over the last 10 years initially within the Ifremer-IRD schlerochronology laboratory and the Fisheries Science and Technology department at Ifremer, and then at the Signal & Communication Department of Telecom Bretagne. My research activities were undertaken at the interface of Information Science and Technology and Oceanography. In the framework of interdisciplinary approaches, my research work addressed the development of new image and signal processing tools and methods with a view to (1) providing new representations of the obsvered scenes or processes, (2) exploiting these representations to infer or reconstruct patterns of interest for the considered thematic objectives. Three thematic...
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Ano: 2012 URL: http://archimer.ifremer.fr/doc/00079/19015/16596.pdf
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A HMM-based model to geolocate pelagic fish from high-resolution individual temperature and depth histories: European sea bass as a case study ArchiMer
Woillez, Mathieu; Fablet, Ronan; Tran-thanh Ngo,; Lalire, Maxime; Lazure, Pascal; De Pontual, Helene.
Numerous methods have been developed to geolocate fish from data storage tags. Whereas demersal species have been tracked using tide-driven geolocation models, pelagic species which undertake extensive migrations have been mainly tracked using light-based models. Here, we present a new HMM-based model that infers pelagic fish positions from the sole use of high-resolution temperature and depth histories. A key contribution of our framework lies in model parameter inference (diffusion coefficient and noise parameters with respect to the reference geophysical fields—satellite SST and temperatures derived from the MARS3D hydrodynamic model), which improves model robustness. As a case study, we consider long time series of data storage tags (DSTs) deployed on...
Tipo: Text Palavras-chave: Fish movement; Archival tagging; Migration; Population structure; Hidden Markov Model (HMM); State-space model.
Ano: 2016 URL: http://archimer.ifremer.fr/doc/00300/41097/40270.pdf
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SST spatial anisotropic covariances from METOP-AVHRR data ArchiMer
Tandeo, Pierre; Autret, Emmanuelle; Chapron, Bertrand; Fablet, Ronan; Garello, Rene.
The Advanced Very High Resolution Radiometer (AVHRR) instrument on-board the METOP satellite is designed to provide very accurate measurements of Sea Surface Temperature (SST). In this work, using one year of METOP-AVHRR data and a geostatistical approach, we characterize the spatial anisotropy and non-stationarity of the SST variability using oriented ellipsoids. The method is also able to separate the true SST variability from the artificial error introduced by the METOP-AVHRR sensor. These spatial parameters are then used for producing variability atlases (available on-line) over the whole ocean.
Tipo: Text Palavras-chave: SST; METOP-AVHRR; Spatial variability; Anisotropy.
Ano: 2014 URL: http://archimer.ifremer.fr/doc/00165/27586/25818.pdf
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Intercomparison of data-driven and learning-based interpolations of along-track Nadir and wide-swath Swot altimetry observations ArchiMer
Beauchamp, Maxime; Fablet, Ronan; Ubelmann, Clément; Ballarotta, Maxime; Chapron, Bertrand.
Over the last years, a very active field of research aims at exploring new data-driven and  learning-based methodologies to propose computationally efficient strategies able to benefit from  the large amount of observational remote sensing and numerical simulations for the reconstruction,  interpolation and prediction of high-resolution derived products of geophysical fields. In this paper,  we investigate how they might help to solve for the oversmoothing of the state-of-the-art optimal  interpolation (OI) techniques in the reconstruction of sea surface height (SSH) spatio-temporal  fields. We focus on two small 10° x 10° GULFSTREAM and 8° x 10° OSMOSIS regions, part  of the North-Atlantic basin: the GULFSTREAM area is mainly driven by energetic...
Tipo: Text Palavras-chave: Data-driven and learning-based approaches; Interpolation; Benchmarking; Nadir and SWOT altimetric satellite data; Sea surface height (SSH).
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00648/76052/76996.pdf
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Weakly Supervised Classification of Objects in Images Using Soft Random Forests ArchiMer
Lefort, Riwal; Fablet, Ronan; Boucher, Jean-marc.
The development of robust classification model is among the important issues in computer vision. This paper deals with weakly supervised learning that generalizes the supervised and semi-supervised learning. In weakly supervised learning training data are given as the priors of each class for each sample. We first propose a weakly supervised strategy for learning soft decision trees. Besides, the introduction of elms priors for training samples instead of hard class labels makes natural the formulation of an iterative learning procedure. We report experiments for UCI object recognition datasets. These experiments show that recognition performance close to the supervised learning can be expected using the propose framework. Besides, an application to...
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Ano: 2010 URL: http://archimer.ifremer.fr/doc/00030/14119/11371.pdf
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Data-Driven Interpolation of Sea Level Anomalies Using Analog Data Assimilation ArchiMer
Lguensat, Redouane; Viet, Phi Huynh; Sun, Miao; Chen, Ge; Fenglin, Tian; Chapron, Bertrand; Fablet, Ronan.
From the recent developments of data-driven methods as a means to better exploit large-scale observation, simulation and reanalysis datasets for solving inverse problems, this study addresses the improvement of the reconstruction of higher-resolution Sea Level Anomaly (SLA) fields using analog strategies. This reconstruction is stated as an analog data assimilation issue, where the analog models rely on patch-based and Empirical Orthogonal Functions (EOF)-based representations to circumvent the curse of dimensionality. We implement an Observation System Simulation Experiment (OSSE) in the South China Sea. The reported results show the relevance of the proposed framework with a significant gain in terms of Root Mean Square Error (RMSE) for scales below 100...
Tipo: Text Palavras-chave: Analog data assimilation; Sea level anomaly; Sea surface height; Interpolation; Data-driven methods.
Ano: 2019 URL: https://archimer.ifremer.fr/doc/00489/60078/63402.pdf
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Altimetry for the future: Building on 25 years of progress ArchiMer
Abdalla, Saleh; Abdeh Kolahchi, Abdolnabi; Adusumilli, Susheel; Aich Bhowmick, Suchandra; Alou-font, Eva; Amarouche, Laiba; Andersen, Ole Baltazar; Antich, Helena; Aouf, Lotfi; Arbic, Brian; Armitage, Thomas; Arnault, Sabine; Artana, Camila; Aulicino, Giuseppe; Ayoub, Nadia; Badulin, Sergei; Baker, Steven; Banks, Chris; Bao, Lifeng; Barbetta, Silvia; Barceló-llull, Bàrbara; Barlier, François; Basu, Sujit; Bauer-gottwein, Peter; Becker, Matthias; Beckley, Brian; Bellefond, Nicole; Belonenko, Tatyana; Benkiran, Mounir; Benkouider, Touati; Bennartz, Ralf; Benveniste, Jérôme; Bercher, Nicolas; Berge-nguyen, Muriel; Bettencourt, Joao; Blarel, Fabien; Blazquez, Alejandro; Blumstein, Denis; Bonnefond, Pascal; Borde, Franck; Bouffard, Jérôme; Boy, François; Boy, Jean-paul; Brachet, Cédric; Brasseur, Pierre; Braun, Alexander; Brocca, Luca; Brockley, David; Brodeau, Laurent; Brown, Shannon; Bruinsma, Sean; Bulczak, Anna; Buzzard, Sammie; Cahill, Madeleine; Calmant, Stéphane; Calzas, Michel; Camici, Stefania; Cancet, Mathilde; Capdeville, Hugues; Carabajal, Claudia Cristina; Carrere, Loren; Cazenave, Anny; Chassignet, Eric P.; Chauhan, Prakash; Cherchali, Selma; Chereskin, Teresa; Cheymol, Cecile; Ciani, Daniele; Cipollini, Paolo; Cirillo, Francesca; Cosme, Emmanuel; Coss, Steve; Cotroneo, Yuri; Cotton, David; Couhert, Alexandre; Coutin-faye, Sophie; Crétaux, Jean-françois; Cyr, Frederic; D’ovidio, Francesco; Darrozes, José; David, Cedric; Dayoub, Nadim; De Staerke, Danielle; Deng, Xiaoli; Desai, Shailen; Desjonqueres, Jean-damien; Dettmering, Denise; Di Bella, Alessandro; Díaz-barroso, Lara; Dibarboure, Gerald; Dieng, Habib Boubacar; Dinardo, Salvatore; Dobslaw, Henryk; Dodet, Guillaume; Doglioli, Andrea; Domeneghetti, Alessio; Donahue, David; Dong, Shenfu; Donlon, Craig; Dorandeu, Joël; Drezen, Christine; Drinkwater, Mark; Du Penhoat, Yves; Dushaw, Brian; Egido, Alejandro; Erofeeva, Svetlana; Escudier, Philippe; Esselborn, Saskia; Exertier, Pierre; Fablet, Ronan; Falco, Cédric; Farrell, Sinead Louise; Faugere, Yannice; Femenias, Pierre; Fenoglio, Luciana; Fernandes, Joana; Fernández, Juan Gabriel; Ferrage, Pascale; Ferrari, Ramiro; Fichen, Lionel; Filippucci, Paolo; Flampouris, Stylianos; Fleury, Sara; Fornari, Marco; Forsberg, Rene; Frappart, Frédéric; Frery, Marie-laure; Garcia, Pablo; Garcia-mondejar, Albert; Gaudelli, Julia; Gaultier, Lucile; Getirana, Augusto; Gibert, Ferran; Gil, Artur; Gilbert, Lin; Gille, Sarah; Giulicchi, Luisella; Gómez-enri, Jesús; Gómez-navarro, Laura; Gommenginger, Christine; Gourdeau, Lionel; Griffin, David; Groh, Andreas; Guerin, Alexandre; Guerrero, Raul; Guinle, Thierry; Gupta, Praveen; Gutknecht, Benjamin D.; Hamon, Mathieu; Han, Guoqi; Hauser, Danièle; Helm, Veit; Hendricks, Stefan; Hernandez, Fabrice; Hogg, Anna; Horwath, Martin; Idžanović, Martina; Janssen, Peter; Jeansou, Eric; Jia, Yongjun; Jia, Yuanyuan; Jiang, Liguang; Johannessen, Johnny A.; Kamachi, Masafumi; Karimova, Svetlana; Kelly, Kathryn; Kim, Sung Yong; King, Robert; Kittel, Cecile M.m.; Klein, Patrice; Klos, Anna; Knudsen, Per; Koenig, Rolf; Kostianoy, Andrey; Kouraev, Alexei; Kumar, Raj; Labroue, Sylvie; Lago, Loreley Selene; Lambin, Juliette; Lasson, Léa; Laurain, Olivier; Laxenaire, Rémi; Lázaro, Clara; Le Gac, Sophie; Le Sommer, Julien; Le Traon, Pierre-yves; Lebedev, Sergey; Léger, Fabien; Legresy, Benoı̂t; Lemoine, Frank; Lenain, Luc; Leuliette, Eric; Levy, Marina; Lillibridge, John; Liu, Jianqiang; Llovel, William; Lyard, Florent; Macintosh, Claire; Makhoul Varona, Eduard; Manfredi, Cécile; Marin, Frédéric; Mason, Evan; Massari, Christian; Mavrocordatos, Constantin; Maximenko, Nikolai; Mcmillan, Malcolm; Medina, Thierry; Melet, Angelique; Meloni, Marco; Mertikas, Stelios; Metref, Sammy; Meyssignac, Benoit; Michaël, Ablain; Minster, Jean-françois; Moreau, Thomas; Moreira, Daniel; Morel, Yves; Morrow, Rosemary; Moyard, John; Mulet, Sandrine; Naeije, Marc; Nerem, Robert Steven; Ngodock, Hans; Nielsen, Karina; Nilsen, Jan Even Øie; Niño, Fernando; Nogueira Loddo, Carolina; Noûs, Camille; Obligis, Estelle; Otosaka, Inès; Otten, Michiel; Oztunali Ozbahceci, Berguzar; P. Raj, Roshin; Paiva, Rodrigo; Paniagua, Guillermina; Paolo, Fernando; Paris, Adrien; Pascual, Ananda; Passaro, Marcello; Paul, Stephan; Pavelsky, Tamlin; Pearson, Christopher; Penduff, Thierry; Peng, Fukai; Perosanz, Felix; Picot, Nicolas; Piras, Fanny; Poggiali, Valerio; Poirier, Étienne; Ponce De León, Sonia; Prants, Sergey; Prigent, Catherine; Provost, Christine; Pujol, M-isabelle; Qiu, Bo; Quilfen, Yves; Rami, Ali; Raney, R. Keith; Raynal, Matthias; Remy, Elisabeth; Rémy, Frédérique; Restano, Marco; Richardson, Annie; Richardson, Donald; Ricker, Robert; Ricko, Martina; Rinne, Eero; Rose, Stine Kildegaard; Rosmorduc, Vinca; Rudenko, Sergei; Ruiz, Simón; Ryan, Barbara J.; Salaün, Corinne; Sanchez-roman, Antonio; Sandberg Sørensen, Louise; Sandwell, David; Saraceno, Martin; Scagliola, Michele; Schaeffer, Philippe; Scharffenberg, Martin G.; Scharroo, Remko; Schiller, Andreas; Schneider, Raphael; Schwatke, Christian; Scozzari, Andrea; Ser-giacomi, Enrico; Seyler, Frederique; Shah, Rashmi; Sharma, Rashmi; Shaw, Andrew; Shepherd, Andrew; Shriver, Jay; Shum, C.k.; Simons, Wim; Simonsen, Sebatian B.; Slater, Thomas; Smith, Walter; Soares, Saulo; Sokolovskiy, Mikhail; Soudarin, Laurent; Spatar, Ciprian; Speich, Sabrina; Srinivasan, Margaret; Srokosz, Meric; Stanev, Emil; Staneva, Joanna; Steunou, Nathalie; Stroeve, Julienne; Su, Bob; Sulistioadi, Yohanes Budi; Swain, Debadatta; Sylvestre-baron, Annick; Taburet, Nicolas; Tailleux, Rémi; Takayama, Katsumi; Tapley, Byron; Tarpanelli, Angelica; Tavernier, Gilles; Testut, Laurent; Thakur, Praveen K.; Thibaut, Pierre; Thompson, Luanne; Tintoré, Joaquín; Tison, Céline; Tourain, Cédric; Tournadre, Jean; Townsend, Bill; Tran, Ngan; Trilles, Sébastien; Tsamados, Michel; Tseng, Kuo-hsin; Ubelmann, Clément; Uebbing, Bernd; Vergara, Oscar; Verron, Jacques; Vieira, Telmo; Vignudelli, Stefano; Vinogradova Shiffer, Nadya; Visser, Pieter; Vivier, Frederic; Volkov, Denis; Von Schuckmann, Karina; Vuglinskii, Valerii; Vuilleumier, Pierrik; Walter, Blake; Wang, Jida; Wang, Chao; Watson, Christopher; Wilkin, John; Willis, Josh; Wilson, Hilary; Woodworth, Philip; Yang, Kehan; Yao, Fangfang; Zaharia, Raymond; Zakharova, Elena; Zaron, Edward D.; Zhang, Yongsheng; Zhao, Zhongxiang; Zinchenko, Vadim; Zlotnicki, Victor.
In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and...
Tipo: Text Palavras-chave: Satellite altimetry; Oceanography; Sea level; Coastal oceanography; Cryospheric sciences; Hydrology.
Ano: 2021 URL: https://archimer.ifremer.fr/doc/00688/79999/82978.pdf
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Region based variational approach for the segmentation textured sonar images ArchiMer
Karoui, Imen; Fablet, Ronan; Boucher, Jean-marc; Augustin, Jean-marie.
We propose a new region-based segmentation of textured sonar images with respect to seafloor types. We characterize sea-floor types by a set of empirical distributions estimated on texture responses to a set of different filters and we introduce a novel similarity measure between sonar textures in this attribute space. Our similarity measure is defined as a weighted sum of Kullback-Leibler divergences between texture features. The texture similarity measure weight setting is twofold: first we weight each filter, according to its discrimination power, the computation of these weights are issued from the margin maximization criterion, Second, we add an additional weighting, evaluated as an angular distance between the incidence angles of the compared texture...
Tipo: Text Palavras-chave: Level sets; Active regions; Segmentation; Angular backscattering; Feature selection; Sonar images; Texture.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-6120.pdf
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A review of image-based tools for automatic fish ageing from otolith features ArchiMer
Carbini, Sebastien; Chessel, Anatole; Benzinou, Abdesslam; Fablet, Ronan; Mahe, Kelig; De Pontual, Helene.
Most of European fish stocks are assessed using age-based models, and otolith interpretation for age estimations costs several million euros annually. In this context, automated ageing systems would provide a mean to 1) standardize ageing, 2) control ageing consistency within and between ageing laboratories 3) build interpreted image data bases ensuring the information conservation and sharing and 4) improve growth studies while reducing the cost of the acquisition of age data. This paper presents a review of different image-based tools for automatic fish ageing from otolith features within the framework of AFISA (EU STREP project on Automated FISh Ageing coordinated by Ifremer). The full automatic ageing process can be divided into three main steps: 1)...
Tipo: Text
Ano: 2008 URL: http://archimer.ifremer.fr/doc/00024/13519/10546.pdf
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Neural Network Based Kalman Filters for the Spatio-Temporal Interpolation of Satellite-Derived Sea Surface Temperature ArchiMer
Ouala, Said; Fablet, Ronan; Herzet, Cedric; Chapron, Bertrand; Pascual, Ananda; Collard, Fabrice; Gaultier, Lucile.
The forecasting and reconstruction of oceanic dynamics is a crucial challenge. While model driven strategies are still the state-of-the-art approaches in the reconstruction of spatio-temporal dynamics. The ever increasing availability of data collections in oceanography raised the relevance of data-driven approaches as computationally efficient representations of spatio-temporal fields reconstruction. This tools proved to outperform classical state-of-the-art interpolation techniques such as optimal interpolation and DINEOF in the retrievement of fine scale structures while still been computationally efficient comparing to model based data assimilation schemes. However, coupling this data-driven priors to classical filtering schemes limits their potential...
Tipo: Text Palavras-chave: Data assimilation; Dynamical model; Kalman filter; Neural networks; Data-driven models; Interpolation.
Ano: 2018 URL: https://archimer.ifremer.fr/doc/00481/59286/61979.pdf
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Interpolation par assimilation variationnelle de séquences multimodales d’images satellitaires de l’océan ArchiMer
Ba, Sileye O.; Corpetti, Thomas; Chapron, Bertrand; Fablet, Ronan.
In this paper we address the problem of missing data interpolation in multi-modal geophysical satellite observation sequences. Main issues relate to the large percentage of missing data, from 20 % to 90 % for daily high-resolution observations; and the requirement for reconstructing fine-scale structures in accordance with the underlying turbulent dynamics. To solve the missing data interpolation problem, a variational data assimilation model is developped. Using synthetic and real ocean surface observations, numerical and qualitative evaluations demonstrate the relevance of two key components of the proposed model: the fusion of multi-modal observations through a geometric front-driven constraint and the proposed variational assimilation setting using an...
Tipo: Text Palavras-chave: Assimilation variationnelle de données; Interpolation de données manquantes; Inpainting.; Data assimilation; Variational method; Missing data interpolation; Geophysical tracers dynamics; Multimodal interpolation.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00139/24980/23061.pdf
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Semi-local extraction of ring structures in images of biological hard tissues: application to the Bayesian interpretation of fish otoliths for age and growth estimation ArchiMer
Fablet, Ronan.
This paper deals with the analysis of images of biological tissue that involves ring structures, such as tree trunks, bivalve seashells, or fish otoliths, with a view to automating the acquisition of age and growth data. A bottom-up template-based scheme extracts meaningful ridge and valley curve data using growth-adapted time-frequency filtering. Age and growth estimation is then stated as the Bayesian selection of a subset of ring curves, which combines a measure of curve significativity and an a priori statistical growth model. Experiments on real samples demonstrate the efficiency of the proposed data extraction stage. Our Bayesian framework is shown to significantly outperform previous methods for the interpretation of a data set of 200 plaice...
Tipo: Text Palavras-chave: Bayesian modeling; Automated age and growth estimation; Growth ring extraction; Otolith images; Images of biological hard tissues; Approche bayésienne; Estimation automatiques de l'âge et de la croissance; Extraction automatiques des marques de croissance; Otolithe; Tissus durs.
Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/publication-1705.pdf
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Understanding otolith biomineralization processes: new insights into microscale spatial distribution of organic and mineral fractions from Raman microspectrometry ArchiMer
Jolivet, Aurelie; Bardeau, J.f.; Fablet, Ronan; Paulet, Y.m.; De Pontual, Helene.
It is generally accepted that the formation of otolith microstructures (L- and D-zones) and in particular the organic and mineral fractions vary on a daily basis. Raman microspectrometry provides a nondestructive technique that can be used to provide structural information on organic and mineral compounds. We applied it to thin otolith sections of hake in order to address the following issues: (1) the simultaneous characterization of variations in the organic and mineral fractions both in the core area and along successive otolith microstructures; (2) elucidation of significant differences between these fractions; (3) quantification of the effects of etching and staining protocols on otolith structures. The primordium appeared as a punctual area depicting...
Tipo: Text Palavras-chave: Acid etching; Staining; Aragonite; L and D zones; Core.
Ano: 2008 URL: http://archimer.ifremer.fr/doc/2008/publication-4355.pdf
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Preparation techniques alter the mineral and organic fractions of fish otoliths: insights using Raman micro-spectrometry ArchiMer
Jolivet, Aurelie; Fablet, Ronan; Bardeau, Jean-francois; De Pontual, Helene.
The high spatial resolution analysis of the mineral and organic composition of otoliths using Raman micro-spectrometry involves rigorous protocols for sample preparation previously established for microchemistry and trace elements analyses. These protocols often include otolith embedding in chemically neutral resin (i.e., resins which do not contain, in detectable concentration, elements usually sought in the otoliths). Such embedding may however induce organic contamination. In this paper, Raman micro-spectrometry reveals the presence of organic contamination onto the surface obtained from the use of epoxy resin, specifically Araldite. This contamination level varies depending on otolith structures. Core and checks, known as structural discontinuities,...
Tipo: Text Palavras-chave: Epoxy resin; Otolith composition; Microstructure; Raman spectrometry.
Ano: 2013 URL: http://archimer.ifremer.fr/doc/00138/24965/26372.pdf
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Automatic morphological detection of otolith nucleus ArchiMer
Cao, Frédéric; Fablet, Ronan.
This paper deals with the automation of the acquisition of age and growth data from the analysis of otolith images. One of the key component of such it system is the automatic detection of the growth center, which serves as the basis for further processing (2D ring segmentation, age and growth estimation,...). To this end, we develop a new and well-founded approach combining a morphological analysis of image level sets to the a contrario, detection principle. This approach leads to a robust parameterless scheme, whose efficiency is demonstrated by an evaluation carried out for a set of several hundred of plaice otoliths. (c) 2005 Elsevier B.V. All rights reserved.
Tipo: Text Palavras-chave: Otolith imaging; A contrario detection; Mathematical morphology.
Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/publication-1223.pdf
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Reconstructing Global Chlorophyll-a Variations Using a Non-linear Statistical Approach ArchiMer
Martinez, Elodie; Gorgues, Thomas; Lengaigne, Matthieu; Fontana, Clement; Sauzède, Raphaëlle; Menkes, Christophe; Uitz, Julia; Di Lorenzo, Emanuele; Fablet, Ronan.
Monitoring the spatio-temporal variations of surface chlorophyll-a concentration (Chl, a proxy of phytoplankton biomass) greatly benefited from the availability of continuous and global ocean color satellite measurements from 1997 onward. These two decades of satellite observations are however still too short to provide a comprehensive description of Chl variations at decadal to multi-decadal timescales. This paper investigates the ability of a machine learning approach (a non-linear statistical approach based on Support Vector Regression, hereafter SVR) to reconstruct global spatio-temporal Chl variations from selected surface oceanic and atmospheric physical parameters. With a limited training period (13 years), we first demonstrate that Chl variability...
Tipo: Text Palavras-chave: Machine learning; Phytoplankton variability; Satellite ocean color; Decadel variability; Global scale.
Ano: 2020 URL: https://archimer.ifremer.fr/doc/00641/75314/75810.pdf
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Statistical learning applied to computer-assisted fish age and growth estimation from otolith images ArchiMer
Fablet, Ronan.
Computer-assisted tools need to be developed to help in the accurate and efficient acquisition of fish age and growth data for ecological and assessment issues. Stating fish age and growth analysis as pattern classification issues, the proposed approach relies on a statistical learning strategy. Given otolith images interpreted by an expert, probabilistic kernel-based methods (namely Kernel Logistic Regression) are used to infer interpretation rules. More precisely, two different probabilistic models are introduced: one to infer fish age from otolith images and a second one aiming at evaluating whether or not a given otolith growth pattern is realistic w.r.t. training examples. These probabilistic models provide us with the basis for coping with three...
Tipo: Text Palavras-chave: Computer assisted fish age and growth analysis; Otolith image analysis; Otolith interpretation; Statistical learning.
Ano: 2006 URL: http://archimer.ifremer.fr/doc/2006/publication-2136.pdf
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Spatial Statistics of Objects in 3-D Sonar Images: Application to Fisheries Acoustics ArchiMer
Lefort, Riwal; Fablet, Ronan; Berger, Laurent; Boucher, Jm.
In this letter, we address the characterization of objects in 3-D sonar images of the water column obtained by a multibeam echo sounder. Compared with classic 2-D images from a monobeam echo sounder, these 3-D images provide finer scale observation of the pelagic biomasses and new tools to characterize 3-D distributions. By viewing object patterns as realizations of spatial point processes, we investigate descriptive spatial statistics. This method is then applied to 3-D fisheries acoustics data set for characterization of the distribution of pelagic fish schools. Reported experiments illustrate the relevance of the proposed descriptors. The comparison of our method with 2-D sonar data analysis further demonstrates the information gain from using 3-D sonar...
Tipo: Text Palavras-chave: Fisheries acoustics; Multibeam sensor; Object patterns in images; Point processes; Spatial statistics.
Ano: 2012 URL: http://archimer.ifremer.fr/doc/00056/16769/14270.pdf
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