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Potential for calibrating airborne video imagery using preflight calibration coefficients / A. Edirisinghe in Photogrammetric Engineering & Remote Sensing, PERS, vol 70 n° 5 (May 2004)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 70 n° 5 (May 2004) . - pp 573 - 580 Titre : Potential for calibrating airborne video imagery using preflight calibration coefficients Type de document : Article/Communication Auteurs : A. Edirisinghe, Auteur ; J.P. Louis, Auteur ; G.E. Chapman, Auteur Année de publication : 2004 Article en page(s) : pp 573 - 580 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] caméra vidéo numérique [Termes IGN] capteur aérien [Termes IGN] étalonnage au sol [Termes IGN] étalonnage radiométrique [Termes IGN] image vidéo [Termes IGN] modèle de transfert radiatif Résumé : (Auteur) The low-cost Multispectral Airborne Video System (MAVS), developed using off-the-shelf components, is predominantly being used for agricultural and environmental monitoring applications in Australia. In order to guarantee quality of operational imagery regular radiometric calibration checks, under both preflight and in-flight environments, are a necessity. While preflight calibration is conducted in the field with relative ease, to conduct in-flight calibration checks during operational missions is difficult, especially when onboard calibration instrumentation is not available. The calibration of MAVS imagery in flight requires a radiative transfer code such as the 6S to simulate the radiation signal at the operational altitude. A comparison of the simulated in-flight calibration equation with the corresponding preflight calibration equation showed a statistically significant agreement for every MAVS band, demonstrating the stability of response of the instrument in the air. This MAVS response stability indicates a potential for calibrating operational airborne imagery using preflight calibration equations. A few simulated in-flight calibration checks, in addition to regular preflight calibrations, could still be carried out during the flight season to verify system radiometric response in the air. Numéro de notice : A2004-180 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.70.5.573 En ligne : https://doi.org/10.14358/PERS.70.5.573 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26707 [article]

Seeing the trees in the forest: Using Lidar and multispectral data fusion with local filtering and variable window size for estimating tree height / S.C. Pospecu in Photogrammetric Engineering & Remote Sensing, PERS, vol 70 n° 5 (May 2004)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 70 n° 5 (May 2004) . - pp 589 - 604 Titre : Seeing the trees in the forest: Using Lidar and multispectral data fusion with local filtering and variable window size for estimating tree height Type de document : Article/Communication Auteurs : S.C. Pospecu, Auteur ; R. Wynne, Auteur Année de publication : 2004 Article en page(s) : pp 589 - 604 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] couvert forestier [Termes IGN] données lidar [Termes IGN] estimation statistique [Termes IGN] feuillu [Termes IGN] fusion d'images [Termes IGN] hauteur des arbres [Termes IGN] identification automatique [Termes IGN] image multibande [Termes IGN] modèle de régression [Termes IGN] Pinus (genre) Résumé : (Auteur) The main study objective was to develop robust processing and analysis techniques to facilitate the use of small-footprint lidar data for estimating plot-level tree height by measuring individual trees identifiable on the three-dimensional lidar surface. Lidar processing techniques included data fusion with multispectral optical data and local filtering with both square and circular windows of variable size. The lidar system used for this study produced an average footprint of 0.65 m and an average distance between laser shots of 0.7 m. The lidar data set was acquired over deciduous and coniferous stands with settings typical of the southeastern United States. The lidar-derived tree measurements were used with regression models and cross-validation to estimate tree height on 0.017-ha plots. For the pine plots, lidar measurements explained 97 percent of the variance associated with the mean height of dominant trees. For deciduous plots, regression models explained 79 percent of the mean height variance for dominant trees. Filtering for local maximum with circular windows gave better fitting models for pines, while for deciduous trees, filtering with square windows provided a slightly better model fit. Using lidar and optical data fusion to differentiate between forest types provided better results for estimating average plot height for pines. Estimating tree height for deciduous plots gave superior results without calibrating the search window size based on forest type. Numéro de notice : A2004-181 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.70.5.589 En ligne : https://doi.org/10.14358/PERS.70.5.589 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26708 [article]

An integrated approach for landslide susceptibility mapping using remote sensing and GIS / S. Sarkar in Photogrammetric Engineering & Remote Sensing, PERS, vol 70 n° 5 (May 2004)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 70 n° 5 (May 2004) . - pp 617 - 625 Titre : An integrated approach for landslide susceptibility mapping using remote sensing and GIS Type de document : Article/Communication Auteurs : S. Sarkar, Auteur ; D.P. Kanungo, Auteur Année de publication : 2004 Article en page(s) : pp 617 - 625 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] cartographie des risques [Termes IGN] classification [Termes IGN] couche thématique [Termes IGN] données de terrain [Termes IGN] effondrement de terrain [Termes IGN] Himalaya [Termes IGN] image IRS [Termes IGN] risque naturel [Termes IGN] système d'information géographique Résumé : (Auteur) A methodology for landslide susceptibility mapping using an integrated remote sensing and GIS approach is presented. A part of the Darjeeling Himalaya was selected for the model execution. IRS satellite data, topographic maps, field data, and other informative maps were used as inputs to the study. Important terrain factors, contributing to landslide occurrences in the region, were identified and corresponding thematic data layers were generated. These data layers represent the geological, topographical, and hydrological conditions of the terrain. A numerical rating scheme for the factors was developed for spatial data analysis in a GIS. The resulting landslide susceptibility map delineates the area into different zones of four relative susceptibility classes: high, moderate, low, and very low. The susceptibility map was validated by correlating the landslide frequencies of different classes. This has shown a close agreement with the existing field instability condition. The effectiveness of the map was also confirmed by the high statistically significant value of a chi-square test. Numéro de notice : A2004-182 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.70.5.617 En ligne : https://doi.org/10.14358/PERS.70.5.617 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26709 [article]

Thematic map comparison: evaluating the statistical significance of differences in classification accuracy / Giles M. Foody in Photogrammetric Engineering & Remote Sensing, PERS, vol 70 n° 5 (May 2004)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 70 n° 5 (May 2004) . - pp 627 - 633 Titre : Thematic map comparison: evaluating the statistical significance of differences in classification accuracy Type de document : Article/Communication Auteurs : Giles M. Foody, Auteur Année de publication : 2004 Article en page(s) : pp 627 - 633 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] analyse comparative [Termes IGN] carte thématique [Termes IGN] données de terrain [Termes IGN] échantillon [Termes IGN] Kappa de Cohen [Termes IGN] précision de la classification Résumé : (Auteur) The accuracy of thematic maps derived by image classification analyses is often compared in remote sensing studies. This comparison is typically achieved by a basic subjective assessment of the observed difference in accuracy but should be undertaken in a statistically rigorous fashion. One approach for the evaluation of the statistical significance of a difference in map accuracy that has been widely used in remote sensing research is based on the comparison of the kappa coefficient of agreement derived for each map. The conventional approach to the comparison of kappa coefficients assumes that the samples used in their calculation are independent, an assumption that is commonly unsatisfied because the same sample of ground data sites is often used for each map. Alternative methods to evaluate the statistical significance of differences in accuracy are available for both related and independent samples. Approaches for map comparison based on the kappa coefficient and proportion of correctly allocated cases, the two most widely used metrics of thematic map accuracy in remote sensing, are discussed. An example illustrates how classifications based on the some sample of ground data sites may be compared rigorously and highlights the importance of distinguishing between one- and two-sided statistical tests in the comparison of classification accuracy statements. Numéro de notice : A2004-183 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.70.5.627 En ligne : https://doi.org/10.14358/PERS.70.5.627 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=26710 [article]