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Geometric Correction and Digital Elevation Extraction Using Multiple MTI Datasets / J.A. Mercier in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 2 (February 2007)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 2 (February 2007) . - pp 133 - 142 Titre : Geometric Correction and Digital Elevation Extraction Using Multiple MTI Datasets Type de document : Article/Communication Auteurs : J.A. Mercier, Auteur ; R.A. Schowengerdt, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 133 - 142 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] extraction du sursol [Termes IGN] image MTI [Termes IGN] modèle numérique de surface [Termes IGN] modèle stéréoscopique [Termes IGN] Multispectral thermal imager [Termes IGN] orientation externe [Termes IGN] orientation interne [Termes IGN] pas d'échantillonnage au sol [Termes IGN] précision géométrique (imagerie) Résumé : (Auteur) Digital Elevation Models (DEMs) are traditionally acquired from a stereo pair of aerial photographs sequentially captured by an airborne metric camera. Standard DEM extraction techniques can be naturally extended to satellite imagery, but the particular characteristics of satellite imaging can cause difficulties. The spacecraft ephemeris with respect to the ground site during image collects is the most important factor in the elevation extraction process. When the angle of separation between the stereo images is small, the extraction process typically produces measurements with low accuracy, while a large angle of separation can cause an excessive number of erroneous points in the DEM from occlusion of ground areas. The use of three or more images registered to the same ground area can potentially reduce these problems and improve the accuracy of the extracted DEM. The pointing capability of some sensors, such as the Multispectral Thermal Imager (MTI), allows for multiple collects of the same area from different perspectives. This functionality of MTI makes it a good candidate for the implementation of a DEM extraction algorithm using multiple images for improved accuracy. Evaluation of this capability and development of algorithms to geometrically model the MTI sensor and extract DEMs from multi-look MTI imagery are described in this paper. An RMS elevation error of 6.3-meters is achieved using 11 ground test points, while the MTI band has a 5-meter ground sample distance. Copyright ASPRS Numéro de notice : A2007-059 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.2.133 En ligne : https://doi.org/10.14358/PERS.73.2.133 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28424 [article]

An experiment using a circular neighborhood to calculate slope gradient from a DEM / X. Shi in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 2 (February 2007)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 2 (February 2007) . - pp 143 - 154 Titre : An experiment using a circular neighborhood to calculate slope gradient from a DEM Type de document : Article/Communication Auteurs : X. Shi, Auteur ; A - Xing Zhu, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 143 - 154 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] classification par maximum de vraisemblance [Termes IGN] données matricielles [Termes IGN] gradient de pente [Termes IGN] modèle numérique de surface [Termes IGN] pente [Termes IGN] relation topologique [Termes IGN] relief [Termes IGN] voisinage (relation topologique) Résumé : (Auteur) The traditional 3 X 3 cell neighbourhood used in a focal operation on a raster layer has a square shape that results in a dimensional neighbourhood of which the orientation is eventually arbitrary to the physical features represented. This paper presents an experiment using a circular neighbourhood to calculate slope gradient. Comparisons of the results from a circular neighbourhood with the results from some traditional methods show that (a) for a smooth surface, the result from a circular neighbourhood is more accurate than that from a square neighbourhood, (b) a circular neighbourhood is generally more sensitive to noise in the input DEM than a square neighbourhood, and (c) in a validation using field measurements, the circular neighbourhood performs better than the square neighbourhood when the ratio of user-specified neighbourhood size to cell size is high. Copyright ASPRS Numéro de notice : A2007-060 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.2.143 En ligne : https://doi.org/10.14358/PERS.73.2.143 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28425 [article]