Centre de documentation
scientifique

Use of multi-temporal and multi-sensor data for continental water body extraction in the context of the SWOT mission / Nicolas Gasnier (2022)  

Public Titre : Use of multi-temporal and multi-sensor data for continental water body extraction in the context of the SWOT mission Type de document : Thèse/HDR Auteurs : Nicolas Gasnier, Auteur ; Florence Tupin, Directeur de thèse ; Loïc Denis, Directeur de thèse Editeur : Paris : Institut Polytechnique de Paris Année de publication : 2022 Importance : 213 p. Format : 21 x 30 cm Note générale : Bibliographie Thèse de doctorat présentée à l’Institut Polytechnique de Paris, spécialité Images Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] base de données localisées [Termes IGN] détection d'objet [Termes IGN] détection de changement [Termes IGN] données hydrographiques [Termes IGN] hauteurs de mer [Termes IGN] image multitemporelle [Termes IGN] image radar moirée [Termes IGN] image Sentinel-SAR [Termes IGN] image SWOT [Termes IGN] lac [Termes IGN] rivière [Termes IGN] série temporelle [Termes IGN] télédétection en hyperfréquence Index. décimale : THESE Thèses et HDR Résumé : (Auteur) Spaceborne remote sensing provides hydrologists and decision-makers with data that are essential for understanding the water cycle and managing the associated resources and risks. The SWOT satellite, which is a collaboration between the French (CNES) and American (NASA, JPL) space agencies, is scheduled for launch in 2022 and will measure the height of lakes, rivers, and oceans with high spatial resolution. It will complement existing sensors, such as the SAR and optical constellations Sentinel-1 and 2, and in situ measurements. SWOT represents a technological breakthrough as it is the first satellite to carry a near-nadir swath altimeter. The estimation of water levels is done by interferometry on the SAR images acquired by SWOT. Detecting water in these images is therefore an essential step in processing SWOT data, but it can be very difficult, especially with low signal-to-noise ratios, or in the presence of unusual radiometries. In this thesis, we seek to develop new methods to make water detection more robust. To this end, we focus on the use of exogenous data to guide detection, the combination of multi-temporal and multi-sensor data and denoising approaches. The first proposed method exploits information from the river database used by SWOT (derived from GRWL) to detect narrow rivers in the image in a way that is robust to both noise in the image, potential errors in the database, and temporal changes. This method relies on a new linear structure detector, a least-cost path algorithm, and a new Conditional Random Field segmentation method that combines data attachment and regularization terms adapted to the problem. We also proposed a method derived from GrabCut that uses an a priori polygon containing a lake to detect it on a SAR image or a time series of SAR images. Within this framework, we also studied the use of a multi-temporal and multi-sensor combination between Sentinel-1 SAR and Sentinel-2 optical images. Finally, as part of a preliminary study on denoising methods applied to water detection, we studied the statistical properties of the geometric temporal mean and proposed an adaptation of the variational method MuLoG to denoise it. Note de contenu : 1. Introduction 1.1 Context 1.2 Contributions 1.3 Organization of the manuscript I BACKGROUND ON SAR REMOTE SENSING AND WATER SURFACE MONITORING WITH SAR IMAGES 2. SAR images 2.1 Physics and statistics of SAR images 2.2 The SWOT mission 2.3 Sentinel-1 3. SAR water detection and hydrological prior 3.1 Water detection in SAR images 3.2 SWOT processing and products 3.3 Prior water masks and databases 4. Methodological background 4.1 Markov random fields 4.2 Variational methods for image denoising PROPOSED APPROACHES 5. Guided extraction of narrow rivers on SAR images using an exogenous river database 5.1 Introduction 5.2 Proposed river segmentation pipeline 5.3 Experimental results 5.4 Conclusion 6. Adaptation of the GrabCut method to SAR images: lake detection from a priori polygon 6.1 Single-date GrabCut method for lake detection from a priori polygon 6.2 Multitemporal and multi-sensor adaptations of the method 6.3 2D+T GrabCut of SAR images with temporal regularization for lake detection within an a priori mask 6.4 Joint 2D+T segmentation of SAR and optical images 7. Denoising of the temporal geometric mean 7.1 Introduction 7.2 Statistics of the temporal geometric mean of SAR intensities 7.3 Denoising method 7.4 Experiments 7.5 Application to change detection 7.6 Application to ratio-based denoising of single SAR images within a time series 7.7 Conclusion 8 Conclusion and perspectives Numéro de notice : 26762 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse française Note de thèse : Thèse de Doctorat : Images : Palaiseau : 2022 Organisme de stage : Télécom Paris nature-HAL : Thèse DOI : sans Date de publication en ligne : 17/02/2022 En ligne : https://tel.hal.science/tel-03578831/ Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=99823