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Remote sensing image thresholding methods for determining landslide activity / P.L. Rosin in International Journal of Remote Sensing IJRS, vol 26 n° 6 (March 2005)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 26 n° 6 (March 2005) . - pp 1075 - 1092 Titre : Remote sensing image thresholding methods for determining landslide activity Type de document : Article/Communication Auteurs : P.L. Rosin, Auteur ; J. Hervas, Auteur Année de publication : 2005 Article en page(s) : pp 1075 - 1092 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] analyse comparative [Termes IGN] analyse de groupement [Termes IGN] effondrement de terrain [Termes IGN] filtrage numérique d'image [Termes IGN] image satellite [Termes IGN] Italie [Termes IGN] orthorectification [Termes IGN] seuillage d'image Résumé : (Auteur) Detecting landslides and monitoring their activity is of great relevance for disastrer prevention, preparedness and mitigation in hilly areas. To this end, change detection techniques were developed and applied to multi-temporal digital aerial photographs, simulating the very high spatial resolution of new satellite sensor optical imagery, over the Tessina complex landslide in north-eastern Italy. Several automatic thresholding algorithms are compared on the difference orthorectified and radiometrically normalized images, including some standard methods based on clustering, statistics, moment and entropy, as well as some more novel techniques previously developed by the authors. In addition, a variety of filters were employed to eliminate much of the underisable residual clutter in the thresholded difference image, mainly as a result of natural vegetation and man-land cover changes. These filters are based on shape and size properties of the connected sets of pixels in the threshold maps. This has enabled us discriminate most ground surface changes related to the movement of a pre-existing landslide. Numéro de notice : A2005-144 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160512331330481 En ligne : https://doi.org/10.1080/01431160512331330481 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27282 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-05061	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt

Estimating tropical pasture quality at canopy level using band depth analysis with continuum removal in the visible domain / Onisimo Mutanga in International Journal of Remote Sensing IJRS, vol 26 n° 6 (March 2005)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 26 n° 6 (March 2005) . - pp 1093 - 1108 Titre : Estimating tropical pasture quality at canopy level using band depth analysis with continuum removal in the visible domain Type de document : Article/Communication Auteurs : Onisimo Mutanga, Auteur ; Andrew K. Skidmore, Auteur ; et al., Auteur Année de publication : 2005 Article en page(s) : pp 1093 - 1108 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] analyse spectrale [Termes IGN] bande visible [Termes IGN] contrôle qualité [Termes IGN] faune [Termes IGN] forêt tropicale [Termes IGN] herbe [Termes IGN] paturage [Termes IGN] radiométrie [Termes IGN] réflectance végétale [Termes IGN] régression linéaire [Termes IGN] zone intertropicale Résumé : (Auteur) Pasture quality, expressed as a percentage of total digestible nutients (nitrogen, potassium, phosphorous, calcium and magnesium) is a major factor determining the grazing patterns of wildlife and livestock. Existing rangeland monitoring techniques seldom reflect the nutritive quality of the pastures and are consequently of limited value in explaining animal distribution. Techniques that can estimate pasture quality on a large scale are therefore critical in understanding and explaining wildlife and livestock distribution. We present the results of a greenhouse experiment designed to estimate the concentrations of nitrogen, potassium, phosphorous calcium, magnesium and non-detergent fibre (NDF), using the reflectance of a tropical grass (Cenchrus ciliaris) canopy. Canopy spectral measurements were taken under controlled laboratory conditins using a GER 3700 spectroradiometer. We tested the utility of using the band depth analysis methodology in the visible region (where water absorption is less effective) to estimate foliar chemistry in fresh canopies. Continuum removal was applied to the visible absorption feature centred at 670 nm, and band depth ratios (BDRs) were calculated. Stepwise linear regression was used to select wavelenghts from calculated BDRs that were highly correlated with foliar chemistry in randomly selected training dataset. The resulting regression models were used to predict foliar chemistry in a test dataset. Results indicate that stepwise regression models on band calculated from continuum-removed reflectance spectra could predict foliar nutrient concentration with high accuracy. The correlations were highest for magnesium and nitrogen (R2= 0.77 and 0.73 respectively, using the normalized band depth index (NDBI) between the measured and estimated biochemicals - a satisfactory result in estimating foliar chemistry in fresh standing pastures. With the advent of new sensors such as Hymap and MERIS these results lay the basis for developing algorithms to rapidly estimate and ultimately map pasture quality in tropical rangelands. Numéro de notice : A2005-145 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160512331326738 En ligne : https://doi.org/10.1080/01431160512331326738 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27283 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-05061	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt

Automatic detection of oil spills from SAR images / F. Nirchio in International Journal of Remote Sensing IJRS, vol 26 n° 6 (March 2005)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 26 n° 6 (March 2005) . - pp 1157 - 1174 Titre : Automatic detection of oil spills from SAR images Type de document : Article/Communication Auteurs : F. Nirchio, Auteur ; M. Sorgente, Auteur ; et al., Auteur Année de publication : 2005 Article en page(s) : pp 1157 - 1174 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] classification [Termes IGN] détection automatique [Termes IGN] image ERS-SAR [Termes IGN] modèle stochastique [Termes IGN] pétrole [Termes IGN] pollution des mers [Termes IGN] risque environnemental [Termes IGN] surveillance écologique Résumé : (Auteur) A probalistic method has been developed that distinguishes oil spills from other similar sea surface features in synthetic aperture radar (SAR) images. It considers both the radiometric and geometric characteristics of the areas being tested. In order to minimize the operator intervention, it adopts automatic selection criteria to extract the potentially polluted areas from the images. The method has an a priori percentage of correct classification higher than 90% on the training dataset ; the performance is confirmed on a different dataset of verified slicks. Some analysis have been conducted using images with different radiometric and geometric resolutions to test its suitability with SAR images different from European Remote Sensing (ERS) satellite ones. The system and its ability to detect and classify oil and non-oil surface features are described. Starting from a set of verified oil spills detected offshore and over coastline, the ability of SAR to reveal oil spills is tested by analysing wind intensity, deduced from the images itself, and the distance from the coast. Numéro de notice : A2005-146 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/01431160512331326558 En ligne : https://doi.org/10.1080/01431160512331326558 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27284 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-05061	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt