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Digital surface model generation from CORONA satellite images / A. Altamaier 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 221 - 235 Titre : Digital surface model generation from CORONA satellite images Type de document : Article/Communication Auteurs : A. Altamaier, Auteur ; C. Kany, Auteur Année de publication : 2002 Article en page(s) : pp 221 - 235 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes IGN] cartographie thématique [Termes IGN] GPS en mode cinématique [Termes IGN] image Corona [Termes IGN] image satellite [Termes IGN] modèle numérique de surface [Termes IGN] modèle stéréoscopique [Termes IGN] orthophotographie Résumé : (Auteur) Digital surface models (DSMs) are used for various analyses in environmental science, e.g. for erosion and water studies. Aerial photos and maps, which are necessary for the extraction of DSMs, often do not exist due to financial or political reasons. This situation can be also encountered in Morocco and, in particular, a test area of the international research project IMPETUS was used in this study. Therefore, stereo satellite images of CORONA have been used, as they allow DSM generation, have a ground resolution of 1.83 m, reasonable price (US$1218 per filmstrip of 188 X 14 km) and large coverage (especially of Asia and eastem Europe). The software program ERDAS IMAGINE OrthoBASE Pro was used to generate DSMs automatically from CORONA satellite images with best vertical accuracy of about 10 m and planimetric accuracy of about 3 m. These DSMs could afterwards be used to generate orthoimages, e.g. for mapping change detection and generating thematic maps or land use classifications. Copyright ISPRS Numéro de notice : A2002-166 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/S0924-2716(02)00046-1 En ligne : https://doi.org/10.1016/S0924-2716(02)00046-1 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22081 [article]

Exemplaires(1)

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

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

Integration of classification methods for improvement of land-cover map accuracy / XiaoHang Liu 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 257 - 268 Titre : Integration of classification methods for improvement of land-cover map accuracy Type de document : Article/Communication Auteurs : XiaoHang Liu, Auteur ; Andrew K. Skidmore, Auteur ; H.V. Oosten, Auteur Année de publication : 2002 Article en page(s) : pp 257 - 268 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] analyse comparative [Termes IGN] carte d'occupation du sol [Termes IGN] classification à base de connaissances [Termes IGN] classification par maximum de vraisemblance [Termes IGN] classification par réseau neuronal [Termes IGN] occupation du sol Résumé : (Auteur) Classifiers, which are used to recognize patterns in remotely sensing images, have complementary capabilities. This study tested whether integrating the results from individual classifiers improves classification accuracy. Two integrated approaches were undertaken. One approach used a consensus builder (CS13) to adjust classification output in the case of disagreement in classification between maximum likelihood classifier (MLC), expert system classifier (ESC) and neural network classifier (NNC). If the output classes for each individual pixel differed, the producer accuracies for each class were compared and the class with the highest producer accuracy was assigned to the pixel. The consensus builder approach resulted in a classification with a slightly lower accuracy (72%) when compared with the neural network classifier (74%), but it did significantly better than the maximum likelihood (62%) and expert system (59%) classifiers. The second approach integrated a rulebased expert system classifier and a neural network classifier. The output of the expert system classifier was used as one additional new input layer of the neural network classifier. A postprocessing using the producer accuracies and some additional expert rules was applied to improve the output of the integrated classifier. This is a relatively new approach in the field of image processing. This second approach produced the highest overall accuracy (80%). Thus, incorporating correct, complete and relevant expert knowledge in a neural network classifier leads to higher classification accuracy. Copyright ISPRS Numéro de notice : A2002-168 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/S0924-2716(02)00061-8 En ligne : https://doi.org/10.1016/S0924-2716(02)00061-8 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22083 [article]

Exemplaires(1)

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

Application of snakes and dynamic programming optimisation technique in modeling of buildings in informal settlement areas / H. Ruther 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 269 - 282 Titre : Application of snakes and dynamic programming optimisation technique in modeling of buildings in informal settlement areas Type de document : Article/Communication Auteurs : H. Ruther, Auteur ; H.M. Martine, Auteur ; E.G. Mtalo, Auteur Année de publication : 2002 Article en page(s) : pp 269 - 282 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes IGN] contour [Termes IGN] détection du bâti [Termes IGN] modèle mathématique [Termes IGN] modèle numérique de surface [Termes IGN] orthophotographie [Termes IGN] photographie aérienne [Termes IGN] processeur Résumé : (Auteur) This paper presents a novel approach to semiautomatic building extraction in informal settlement areas from aerial photographs. The proposed approach uses a strategy of delineating buildings by optimising their approximate building contour position. Approximate building contours are derived automatically by locating elevation blobs in digital surface models. Building extraction is then effected by means of the snakes algorithm and the dynamic programming optimisation technique. With dynamic programming, the building contour optimisation problem is realized through a discrete multistage process and solved by the "timedelayed" algorithm, as developed in this work. The proposed building extraction approach is a semiautomatic process, with usercontrolled operations linking fully automated subprocesses. Inputs into the proposed building extraction system are orthoimages and digital surface models, the latter being generated through image matching techniques. Buildings are modeled as "lumps" or elevation blobs in digital surface models, which are derived by altimetric thresholding of digital surface models. Initial windows for building extraction are provided by projecting the elevation blobs centre points onto an orthoimage. In the next step, approximate building contours are extracted from the orthoimage by region growing constrained by edges. Approximate building contours thus derived are inputs into the dynamic programming optimisation process in which final building contours are established. The proposed system is tested on two study areas: Marconi Beam in Cape Town, South Africa, and Manzese in Dar es Salaam, Tanzania. Sixty percent of buildings in the study areas have been extracted and verified and it is concluded that the proposed approach contributes meaningfully to the extraction of buildings in moderately complex and crowded informal settlement areas. Copyright ISPRS Numéro de notice : A2002-169 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/S0924-2716(02)00062-X En ligne : https://doi.org/10.1016/S0924-2716(02)00062-X Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22084 [article]

Exemplaires(1)

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