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Near real-time flood detection in urban and rural areas using high-resolution synthetic aperture radar images / D.C. Mason in IEEE Transactions on geoscience and remote sensing, vol 50 n° 8 (August 2012)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 50 n° 8 (August 2012) . - pp 3041 - 3052 Titre : Near real-time flood detection in urban and rural areas using high-resolution synthetic aperture radar images Type de document : Article/Communication Auteurs : D.C. Mason, Auteur ; Ian J. Davenport, Auteur ; J.C. Neal, Auteur ; et al., Auteur Année de publication : 2012 Article en page(s) : pp 3041 - 3052 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] Angleterre [Termes IGN] détection [Termes IGN] image TerraSAR-X [Termes IGN] inondation [Termes IGN] temps réel [Termes IGN] zone rurale [Termes IGN] zone urbaine Résumé : (Auteur) A near real-time flood detection algorithm giving a synoptic overview of the extent of flooding in both urban and rural areas, and capable of working during night-time and day-time even if cloud was present, could be a useful tool for operational flood relief management. The paper describes an automatic algorithm using high-resolution synthetic aperture radar (SAR) satellite data that builds on existing approaches, including the use of image segmentation techniques prior to object classification to cope with the very large number of pixels in these scenes. Flood detection in urban areas is guided by the flood extent derived in adjacent rural areas. The algorithm assumes that high-resolution topographic height data are available for at least the urban areas of the scene, in order that a SAR simulator may be used to estimate areas of radar shadow and layover. The algorithm proved capable of detecting flooding in rural areas using TerraSAR-X with good accuracy, classifying 89% of flooded pixels correctly, with an associated false positive rate of 6%. Of the urban water pixels visible to TerraSAR-X, 75% were correctly detected, with a false positive rate of 24%. If all urban water pixels were considered, including those in shadow and layover regions, these figures fell to 57% and 18%, respectively. Numéro de notice : A2012-380 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2011.2178030 Date de publication en ligne : 21/02/2012 En ligne : https://doi.org/10.1109/TGRS.2011.2178030 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31826 [article]

Exemplaires(1)

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065-2012081	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Improving river flood extent delineation from synthetic aperture radar using airborne laser altimetry / D.C. Mason in IEEE Transactions on geoscience and remote sensing, vol 45 n° 12 Tome 1 (December 2007)  

Public [article]  inIEEE Transactions on geoscience and remote sensing > vol 45 n° 12 Tome 1 (December 2007) . - pp 3932 - 3943 Titre : Improving river flood extent delineation from synthetic aperture radar using airborne laser altimetry Type de document : Article/Communication Auteurs : D.C. Mason, Auteur ; M.S. Horritt, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 3932 - 3943 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] analyse comparative [Termes IGN] détection de contours [Termes IGN] données lidar [Termes IGN] image radar moirée [Termes IGN] inondation [Termes IGN] lasergrammétrie [Termes IGN] occupation du sol Résumé : (Auteur) Flood extent maps that are derived from synthetic aperture radar (SAR) images provide spatially distributed data for validating hydraulic models of river flood flow. The accuracy of such maps is reduced by a number of factors, including variation in backscatter from the different land cover types that are adjacent to the flood, changes in returns from the water surface that are caused by different meteorological conditions, and the presence of emergent vegetation. This paper describes how improved accuracy can be achieved by modifying an existing flood extent delineation algorithm to use airborne laser altimetry [light detection and ranging (lidar)] as well as SAR data. The lidar data provide an additional constraint that water line heights should vary smoothly along the flooded reach. The method was tested on a SAR image of a flood for which contemporaneous aerial photography existed, together with lidar data of the un flooded reach. The water line heights of the SAR flood extent that was conditioned on both SAR and lidar data matched the corresponding heights from the aerial photograph water line significantly more closely than those from the SAR flood extent that was conditioned only on SAR data. For water line heights in areas of low slope and vegetation, the root-mean-square error on the height differences reduced from 221.1 cm for the latter case to 55.5 cm for the former. Numéro de notice : A2007-584 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1109/TGRS.2007.901032 En ligne : https://doi.org/10.1109/TGRS.2007.901032 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28947 [article]

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065-07121A	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Extraction of tidal channel networks from aerial photographs alone and combined with laser altimetry / Bharat Lohani in International Journal of Remote Sensing IJRS, vol 27 n°1-2 (January 2006)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 27 n°1-2 (January 2006) Titre : Extraction of tidal channel networks from aerial photographs alone and combined with laser altimetry Type de document : Article/Communication Auteurs : Bharat Lohani, Auteur ; D.C. Mason, Auteur ; T.R. Scott, Auteur ; B. Sreenivas, Auteur Année de publication : 2006 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] détection de contours [Termes IGN] données lidar [Termes IGN] fusion d'images [Termes IGN] fusion de données [Termes IGN] identification automatique [Termes IGN] image multibande [Termes IGN] marais salé [Termes IGN] océanographie dynamique [Termes IGN] sédimentation Résumé : (Auteur) Tidal channel networks play an important role in the intertidal zone, exerting substantial control over the hydrodynamics and sediment transport of the region and hence over the evolution of the salt marshes and tidal flats. The study of the morphodynamics of tidal channels is currently an active area of research, and a number of theories have been proposed which require for their validation measurement of channels over extensive areas. Remotely sensed data provide a suitable means for such channel mapping. The paper describes a technique that may be adapted to extract tidal channels from either aerial photographs or LiDAR data separately, or from both types of data used together in a fusion approach. Application of the technique to channel extraction from LiDAR data has been described previously. However, aerial photographs of intertidal zones are much more commonly available than LiDAR data, and most LiDAR flights now involve acquisition of multispectral images to complement the LiDAR data. In view of this, the paper investigates the use of multispectral data for semiautomatic identification of tidal channels, firstly from only aerial photographs or linescanner data, and secondly from fused linescanner and LiDAR data sets. A multi-level, knowledge-based approach is employed. The algorithm based on aerial photography can achieve a useful channel extraction, though may fail to detect some of the smaller channels, partly because the spectral response of parts of the non-channel areas may be similar to that of the channels. The algorithm for channel extraction from fused LiDAR and spectral data gives an increased accuracy, though only slightly higher than that obtained using LiDAR data alone. The results illustrate the difficulty of developing a fully automated method, and justify the semi-automatic approach adopted. Numéro de notice : A2006-058 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160500206692 En ligne : https://doi.org/10.1080/01431160500206692 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27785 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-06011	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Application of airborne scanning laser altimetry to the study of the tidal channel geomorphology / Bharat Lohani in ISPRS Journal of photogrammetry and remote sensing, vol 56 n° 2 (December 2001 - March 2002)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 56 n° 2 (December 2001 - March 2002) . - pp 100 - 120 Titre : Application of airborne scanning laser altimetry to the study of the tidal channel geomorphology Type de document : Article/Communication Auteurs : Bharat Lohani, Auteur ; D.C. Mason, Auteur Année de publication : 2001 Article en page(s) : pp 100 - 120 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] estuaire [Termes IGN] extraction [Termes IGN] géomorphologie [Termes IGN] marée océanique [Termes IGN] marégraphie [Termes IGN] océanographie dynamique [Termes IGN] sédimentologie [Termes IGN] segmentation d'image [Termes IGN] télémétrie laser aéroporté Résumé : (Auteur) Tidal channel play a fundamental role in the hydrodynamic and morphological processes operating within a tidal basin. Conventional means of mapping intertidal zones are either too cumbersome or do not provide sufficient information for accurate quantitative measurements of the channels. This paper describes the use of the airborne scanning altimetry (light detection and ranging-LIDAR) for studying tidal channel morphology. The main emphasis is on developing a technique for extracting tidal channels from LiDAR data. Some common existing techniques of fluvial channel extraction are evaluated with LiDAR data of tidal basins and found moderate in performance. A semiautomatic approach is proposed which has a performance better than that of existing techniques. This approach is realised using an adaptative height thresholding technique to locate channel fragments. A channel joining mechanism then connects the channel fragment using weighted distance transform. The paper also describes briefly an automatic procedure to carry out measurments on the basin image and derive geomorphological parameters such as drainage density. The results obtained illustrate differences in the geomorphology of tidal and terrestrial basins. Copyright ISPRS Numéro de notice : A2001-209 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/S0924-2716(01)00041-7 En ligne : https://doi.org/10.1016/S0924-2716(01)00041-7 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21903 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-01031	SL	Revue	Centre de documentation	Revues en salle	Disponible

Image processing of airborne scanning laser altimetry data for improved river flood modelling / D.M. Cobby in ISPRS Journal of photogrammetry and remote sensing, vol 56 n° 2 (December 2001 - March 2002)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 56 n° 2 (December 2001 - March 2002) . - pp 121 - 138 Titre : Image processing of airborne scanning laser altimetry data for improved river flood modelling Type de document : Article/Communication Auteurs : D.M. Cobby, Auteur ; D.C. Mason, Auteur ; Ian J. Davenport, Auteur Année de publication : 2001 Article en page(s) : pp 121 - 138 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] détection de contours [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] erreur moyenne quadratique [Termes IGN] extraction [Termes IGN] inondation [Termes IGN] modèle de simulation [Termes IGN] modèle hydrographique [Termes IGN] prévention des risques [Termes IGN] segmentation d'image [Termes IGN] télémétrie laser aéroporté Résumé : (Auteur) Airborne scanning laser altimetry (LiDAR) is an important new data source for environmental applications, being able to map topographic height, and the height of surface objects, to high vertical and horizontal accuracy over large areas. This paper describes a range image segmentation system for data from a LiDAR measuring either time of last significant return, or measuring time of both first and last returns. We focus on the application of the segmenter to improving the data required by 2D hydraulic flood models, i.e. maps of topographic height which provide model bathymetry, and vegetation height, which could be converted to distributed floodplain friction coefficients. In addition, the location of river channels and a suitable height contour are used to define the extent of the model domain. An advantage of segmentation is that it allows different topographic and vegetation height extraction algorithms to be used in regions of different cover type. LiDAR data for a reach of the River Severn, UK, is presented. Short vegetation heights (grass and cereal crops) are predicted with a rms error of 14 em. The topography underlying such cover differs from manually measured spot heights by 17 em (rms error). The topographic accuracy decreases in the presence of a densely wooded slope. Errors in the vegetation height map, apparent at the overlap regions of adjacent swaths, are reduced by the removal of heights measured at large scan angles. Copyright ISPRS Numéro de notice : A2001-208 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/S0924-2716(01)00039-9 En ligne : https://doi.org/10.1016/S0924-2716(01)00039-9 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=21902 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-01031	SL	Revue	Centre de documentation	Revues en salle	Disponible

Segmentation of remotely-sensed images by a split-and-merge process / A.M. Cross in International Journal of Remote Sensing IJRS, vol 9 n° 8 (August 1988)  

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