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Mapping coastal vegetation using an expert system and hyperspectral imagery / K.S. Schmidt in Photogrammetric Engineering & Remote Sensing, PERS, vol 70 n° 6 (June 2004)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 70 n° 6 (June 2004) . - pp 703 - 715 Titre : Mapping coastal vegetation using an expert system and hyperspectral imagery Type de document : Article/Communication Auteurs : K.S. Schmidt, Auteur ; Andrew K. Skidmore, Auteur ; et al., Auteur Année de publication : 2004 Article en page(s) : pp 703 - 715 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] analyse comparative [Termes IGN] carte de la végétation [Termes IGN] classification [Termes IGN] image hyperspectrale [Termes IGN] littoral [Termes IGN] marais salé [Termes IGN] Pays-Bas [Termes IGN] photo-interprétation [Termes IGN] photo-interprétation assistée par ordinateur [Termes IGN] photographie aérienne [Termes IGN] plante halophile [Termes IGN] système expert Résumé : (Auteur) Mapping and monitoring saltmarshes in the Netherlands are important activities of the Ministry of Public Works (Rijkswaterstaot). The Survey Department (Meetkundige Dienst) produces vegetation maps using aerial photographs. However, it is a time-consuming and expensive activity. The accuracy of the conventional vegetation map derived using aerial photograph interpretation (API) is estimated to be around 43 percent. In this study, an alternative method is demonstrated that uses an expert system to combine airborne hyperspectral imagery with terrain data derived from radar altimetry The accuracy of the vegetation map generated by the expert system increased to 66 percent. When hyperspectral imagery alone was used to classify coastal wetlands, an accuracy of 40 percent was achieved-comparable to the accuracy of the API-derived vegetation map. An analysis of the efficiency of the proposed expert system showed that the speed of map production is increased by using the new method. This means that digital image classification using the expert system is an objective and repeatable method superior to the conventional API method. Numéro de notice : A2004-205 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.70.6.703 En ligne : https://doi.org/10.14358/PERS.70.6.703 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26732 [article]

Smoothing vegetation spectra with wavelets / K.S. Schmidt in International Journal of Remote Sensing IJRS, vol 25 n° 6 (March 2004)  

Public [article]  inInternational Journal of Remote Sensing IJRS > vol 25 n° 6 (March 2004) . - pp 1167 - 1184 Titre : Smoothing vegetation spectra with wavelets Type de document : Article/Communication Auteurs : K.S. Schmidt, Auteur ; Andrew K. Skidmore, Auteur Année de publication : 2004 Article en page(s) : pp 1167 - 1184 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] filtrage numérique d'image [Termes IGN] lissage de données [Termes IGN] ondelette [Termes IGN] réflectance spectrale [Termes IGN] télédétection en hyperfréquence Résumé : (Auteur) In hyperspectral remote sensing, spectra are increasingly analysed using methods developed for laboratory studies, such as derivative analysis. These techniques require smooth reflectance spectra. Therefore, there is a need for smoothing algorithms that fulfil the requirement of preserving local spectral features while simultaneously removing noise. Noise occurs in variable intensity and over different band widths. Several methods for smoothing a signal exist, including the widely used median and mean filters, the Savitzky-Golay filter applied to laboratory spectra, the cubic spline, and the recently developed transform-based thresholding using the wavelet transform. We compare all these methods using reflectance spectra of the canopy of salt marsh vegetation. The best trade-off between noise reduction and the preservation of spectral features was found to be the wavelet transform, specifically using a translation invariant de-noising based on the non-decimated or stationary wavelet transform. Numéro de notice : A2004-087 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/0143116031000115085 En ligne : https://doi.org/10.1080/0143116031000115085 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26614 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
080-04061	RAB	Revue	Centre de documentation	En réserve L003	Exclu du prêt

Hyperspectral edge filtering for measuring homogeneity of surface cover types / Wim H. Bakker in ISPRS Journal of photogrammetry and remote sensing, vol 56 n° 4 (July - August 2002)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 56 n° 4 (July - August 2002) . - pp 246 - 256 Titre : Hyperspectral edge filtering for measuring homogeneity of surface cover types Type de document : Article/Communication Auteurs : Wim H. Bakker, Auteur ; K.S. Schmidt, Auteur Année de publication : 2002 Article en page(s) : pp 246 - 256 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] distance euclidienne [Termes IGN] eau de mer [Termes IGN] filtrage numérique d'image [Termes IGN] image HYMAP [Termes IGN] image hyperspectrale [Termes IGN] marais Résumé : (Auteur) Edge operators are widely used on grey-level images as a first step in image segmentation or image interpretation. Methods that are currently used for edge filtering are complex and only valid under certain conditions, or useful for threeband colour images only. The problem remains on how to apply edge filtering on multispectral or even hyperspectral images. This paper presents a method that can be used for multispectral and hyperspectral edge filtering. The method uses filtering techniques in combination with three distance measures, namely the Euclidean distance, the spectrum intensity difference, or the spectral angle. The same hyperspectral edge filters serve as homogeneity measures. By simply 'plugging in' another distance measure in the same filter, a separation between intensity and spectral content is achieved, which makes the hyperspectral edge filters the natural extension of colour edge filters. The hyperspectral edge filters use information from all spectral bands to arrive at a (dis)similarity map in one step. The edge filters were tested on HyMap hyperspectral imagery of the island of Schiermormikoog. The test area includes agriculture and a saltmarsh. Experimental results are presented. The spectral angle (dis)similarity of neighbouring pixels can be directly compared with spectral angles already obtained by using the Spectral Angle Mapper for classification. We show that these hyperspectral edge filters assist image interpretation, even in heterogeneous ecosystems such as saltmarshes. Copyright ISPRS Numéro de notice : A2002-167 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/S0924-2716(02)00060-6 En ligne : https://doi.org/10.1016/S0924-2716(02)00060-6 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22082 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-02021	SL	Revue	Centre de documentation	Revues en salle	Disponible