Centre dedocumentation
scientifique

Dépouillements

Semi-automatic identification of submarine pipelines with synthetic aperture sonar Images / Victor Hugo Fernandes in Marine geodesy, Vol 43 n° 4 (July 2020)  

Public [article]  inMarine geodesy > Vol 43 n° 4 (July 2020) . - pp 376 - 395 Titre : Semi-automatic identification of submarine pipelines with synthetic aperture sonar Images Type de document : Article/Communication Auteurs : Victor Hugo Fernandes, Auteur ; Nilcilene Das Graças Medeiros, Auteur ; Dalto Domingues Rodrigues, Auteur ; et al., Auteur Année de publication : 2020 Article en page(s) : pp 376 - 395 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement du signal [Termes IGN] canalisation [Termes IGN] détection de contours [Termes IGN] filtrage du bruit [Termes IGN] scène sous-marine [Termes IGN] sonar Résumé : (Auteur) Synthetic Aperture Sonar (SAS) is a sensor that was designed for hydrographic survey of the seabed. It detects small targets, enabling high geometric resolution images. However, the images generated by SAS are susceptible to speckle noise, which makes digital processing difficult, since the noises are confused with the targets of interest. The goal of this study was to develop a semi-automatic routine for SAS image processing to verify the structural integrity of submarine pipelines. The method presented incorporates four stages: pre-processing to reduce noise and highlight the targets of interest; extraction of features aiming to recognize features related to the pipelines; post-processing to reduce the fragmentation generated during feature extraction; validation to quantify the results from the reference images to estimate the performance of the proposed methodology. The results showed that more than 80% of the submarine pipelines were mapped in the semi-automatic mode, which considerably reduced the time needed to manually identify a large number of pipelines operating on offshore oilfields. Numéro de notice : A2020-248 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01490419.2020.1755916 Date de publication en ligne : 25/04/2020 En ligne : https://doi.org/10.1080/01490419.2020.1755916 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95362 [article]

Evaluations of the significant wave height products of HY-2B satellite radar altimeters / Yongjun Jia in Marine geodesy, Vol 43 n° 4 (July 2020)  

Public [article]  inMarine geodesy > Vol 43 n° 4 (July 2020) . - pp 396 - 413 Titre : Evaluations of the significant wave height products of HY-2B satellite radar altimeters Type de document : Article/Communication Auteurs : Yongjun Jia, Auteur ; Mingsen Lin, Auteur ; Youguang Zhang, Auteur Année de publication : 2020 Article en page(s) : pp 396 - 413 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] analyse comparative [Termes IGN] données Jason [Termes IGN] précision centimétrique [Termes IGN] précision des données Résumé : (Auteur) In the present study, the qualities of the HY-2B along-track significant wave heights (SWH) are assessed, including precision and accuracy. A quality evaluation based on 1 Hz standard deviations is proposed to detect the precision of HY-2B SWH products. The density plots of the (SWH, std) pairs obtained by the HY-2B, Jason-2 and Jason-3 are compared. And the results indicates that the HY-2B SWH root mean square error levels are significantly lower than those observed for the other altimeters. With respect to the SWH obtained from the wave rider buoys, buoys of the National Data Buoy Center (NDBC), Jason-2 and Jason-3, the root mean square errors are 24 cm, 27 cm, 26 cm and 23 cm respectively. The comparison results confirm that the quality of the HY-2B SWH data higher. Numéro de notice : A2020-249 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01490419.2020.1750513 Date de publication en ligne : 10/04/2020 En ligne : https://doi.org/10.1080/01490419.2020.1750513 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95370 [article]

Temporal and spatial variations of monsoonal upwelling along the South West and East coasts of India / Shailee Patel in Marine geodesy, Vol 43 n° 4 (July 2020)  

Public [article]  inMarine geodesy > Vol 43 n° 4 (July 2020) . - pp 414 - 432 Titre : Temporal and spatial variations of monsoonal upwelling along the South West and East coasts of India Type de document : Article/Communication Auteurs : Shailee Patel, Auteur ; Manisha Vithalpura, Auteur ; Subrat Kumar Mallick, Auteur ; Smitha Ratheesh, Auteur Année de publication : 2020 Article en page(s) : pp 414 - 432 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de géodésie spatiale [Termes IGN] aménagement du littoral [Termes IGN] changement climatique [Termes IGN] Inde [Termes IGN] mousson [Termes IGN] série temporelle [Termes IGN] vent Résumé : (Auteur) The implicit/explicit impact of global warming or the anthropogenic climate change on the coastal upwelling processes affects the marine ecosystem significantly and continuous monitoring of the coastal upwelling along the coastal regions is essential. The Ekman transport due to alongshore winds and Ekman pumping due to wind stress curl play important roles on the coastal upwelling, especially along the southern part of Indian peninsula. Upwelling Indexes based on wind and SST are computed in the study to demarcate the upwelling features along the coasts. Since upwelling leaves its trail on surface features, long time series of satellite-derived wind, Sea Surface Temperature (SST), Sea level anomaly (SLA) and Surface Chlorophyll-a concentration (Chl-a) are analyzed to understand the upwelling along the coastal regions of south India. The present study reveals a decrease in the intensity of upwelling along the western coast and a slight increase all along the eastern coast of southern India during summer monsoon. Numéro de notice : A2020-250 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/01490419.2019.1703061 Date de publication en ligne : 19/12/2019 En ligne : https://doi.org/10.1080/01490419.2019.1703061 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95375 [article]