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New methodologies for true orthophoto generation / A.F. Habib in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 1 (January 2007)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 1 (January 2007) . - pp 25 - 36 Titre : New methodologies for true orthophoto generation Type de document : Article/Communication Auteurs : A.F. Habib, Auteur ; E.M. Kim, Auteur ; C.J. Kim, Auteur Année de publication : 2007 Article en page(s) : pp 25 - 36 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Orthophotographie, orthoimage [Termes IGN] artefact [Termes IGN] base de données localisées [Termes IGN] géoréférencement [Termes IGN] grande échelle [Termes IGN] mesure géométrique [Termes IGN] milieu urbain [Termes IGN] modèle numérique de surface [Termes IGN] modèle numérique du bâti [Termes IGN] orthoimage intégrale [Termes IGN] pas d'échantillonnage au sol [Termes IGN] relief Résumé : (Auteur) Orthophoto production aims at the elimination of sensor tilt and terrain relief effects from captured perspective imagery. Uniform scale and the absence of relief displacement in orthophotos make them an important component of GIS databases, where the user can directly determine geographic locations, measure distances, compute areas, and derive other useful information about the area in question. Differential rectification has been traditionally used for orthophoto generation. For large scale imagery over urban areas, differential rectification produces serious artifacts in the form of double mapped areas at object space locations with sudden relief variations, e.g., in the vicinity of buildings. Such artifacts are removed through true orthophoto generation methodologies which are based on the identification of occluded portions of the object space in the involved imagery. Existing methodologies suffer from several problems such as their sensitivity to the sampling interval of the digital surface model (DSM) as it relates to the ground sampling distance (GSD) of the imaging sensor. Moreover, current methodologies rely on the availability of a digital building model (DBM), which requires an additional and expensive pre-processing. This paper presents new methodologies for true orthophoto generation while circumventing the problems associated with existing techniques. The feasibility and performance of the suggested techniques are verified through experimental results with simulated and real data. Copyright ASPRS Numéro de notice : A2007-010 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.1.25 En ligne : https://doi.org/10.14358/PERS.73.1.25 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28376 [article]

Monitoring spatio-temporal dynamics of photosynthesis with a portable hyperspectral imaging system / U. Rascher in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 1 (January 2007)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 1 (January 2007) . - pp 45 - 56 Titre : Monitoring spatio-temporal dynamics of photosynthesis with a portable hyperspectral imaging system Type de document : Article/Communication Auteurs : U. Rascher, Auteur ; C.J. Nichol, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 45 - 56 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] appareil portable [Termes IGN] fluorescence [Termes IGN] image hyperspectrale [Termes IGN] intensité lumineuse [Termes IGN] photosynthèse [Termes IGN] plante non ligneuse [Termes IGN] réflectance végétale [Termes IGN] spectromètre imageur [Termes IGN] stress hydrique [Termes IGN] surveillance de la végétation Résumé : (Auteur) Photosynthetic efficiency of higher plants dynamically adapts to changing light intensity and is greatly influenced by stress, such as water stress. We tested a new portable hyperspectral imaging system, the SOC-700, manufactured by Surface Optics, which produces 12-bit reflectance images between 440 nm and 880 nm with a 4 nm spectral resolution. We quantified the reflectance properties and photochemical reflectance index (PRI) during light adaptation of genetically modified Arabidopsis thaliana (L.) Heynh. plants lacking or over-expressing the PsbS protein, an essential component of the mechanism of non-photochemical dissipation. In a second experiment, PRI images of gradually water stressed leaves were compared to leaf-level measurements of reflectance using a second commercially available spectrometer, and chlorophyll fluorescence to detect dynamic, photosynthesis correlated changes in reflectance and PRI. In both experiments PRI measured with the SOC-700 changed, reflecting the biochemical adaptation of the photosynthetic apparatus to high light intensity (dynamic changes within minutes) and the gradual deactivation of photosynthesis during drying (changes within hours). The quantum efficiency of photosystem II (?F/Fm') and non-photochemical energy dissipation (NPQ) measured from chlorophyll fluorescence, were strongly correlated with PRI. Leaf area PRI values estimated from individual pixel spectra of the SOC-700 quantified photosynthetic efficiency more thoroughly than PRI values calculated from point measurements using the hand-held GER-1500. The applications, limitations, and potential of the SOC-700 for plant eco-physiology and remote sensing are also discussed. Copyright ASPRS Numéro de notice : A2007-011 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.1.45 En ligne : https://doi.org/10.14358/PERS.73.1.45 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28377 [article]

Mapping urban land cover using Quickbird NDVI and GIS spatial modeling for runoff coefficient determination / P. Thanapura in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 1 (January 2007)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 1 (January 2007) . - pp 57 - 65 Titre : Mapping urban land cover using Quickbird NDVI and GIS spatial modeling for runoff coefficient determination Type de document : Article/Communication Auteurs : P. Thanapura, Auteur ; D.L. Helder, Auteur ; S. Burckhard, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 57 - 65 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] bassin hydrographique [Termes IGN] carte d'occupation du sol [Termes IGN] classification non dirigée [Termes IGN] image Quickbird [Termes IGN] modèle mathématique [Termes IGN] Normalized Difference Vegetation Index [Termes IGN] ruissellement [Termes IGN] surface imperméable [Termes IGN] système d'information géographique [Termes IGN] zone urbaine Résumé : (Auteur) This research presents an integration of remote sensing and GIS for determining the runoff coefficient (C) recommended by the American Society of Civil Engineers and the Water Pollution Control Federation in 1969. The C is a runoff index used as an input parameter in the most commonly used procedure: the rational method for storm-water runoff calculation in small urban watersheds for storm drainage design and analysis. The objective of this study was to evaluate 8-bit and 16-bit Quick-Bird (QB) NDVI satellite imagery using an unsupervised classification and the ISODATA algorithm to map impervious area and open space used for the determination of C in GIS spatial modeling. The research hypothesis was that mapping impervious area and open space using high spatial resolution NDVI satellite imagery, generated using the ISODATA algorithm, was an efficient and effective information extraction approach for accurately estimating spatial representative C values. The overall classification accuracies of the six QB NDVI thematic maps produced were similar, about 92 percent. In order to assess the utility of high spatial resolution satellite imagery and to validate the composite runoff index geographic model developed by Thanapura in 2005 and 2006, the C values were calculated in GIS spatial modeling and compared to the industry standard C. Finally, the hypothesis was accepted that the finer resolution image and mapping approach used in this study allowed for better discrimination of land-cover and thus a more accurate representative C estimation. Copyright ASPRS Numéro de notice : A2007-012 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.1.57 En ligne : https://doi.org/10.14358/PERS.73.1.57 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28378 [article]

Performance analysis of integrated sensor orientation / A. Ip in Photogrammetric Engineering & Remote Sensing, PERS, vol 73 n° 1 (January 2007)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 73 n° 1 (January 2007) . - pp 89 - 97 Titre : Performance analysis of integrated sensor orientation Type de document : Article/Communication Auteurs : A. Ip, Auteur ; Naser El-Sheimy, Auteur ; M. Mostafa, Auteur Année de publication : 2007 Article en page(s) : pp 89 - 97 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] aérotriangulation numérique [Termes IGN] capteur imageur [Termes IGN] contrôle qualité automatique [Termes IGN] coût [Termes IGN] élément d'orientation externe [Termes IGN] étalonnage de capteur (imagerie) [Termes IGN] géoréférencement direct [Termes IGN] GPS en mode différentiel [Termes IGN] GPS-INS [Termes IGN] orientation du capteur [Termes IGN] orientation du capteur intégrée [Termes IGN] point d'appui [Termes IGN] qualité des données [Termes IGN] test de performance Résumé : (Auteur) Integrated multi-sensor systems, with their major progress in terms of sensor resolution, data rate and operational flexibility, have become a very attractive mapping tool over the last decade. In aerial mapping application, for example, Exterior Orientation (EO) parameters for the imaging sensors are required. Using the integrated Differential Global Positioning System (DGPS) with Inertial Measurement Units (IMU), direct determination of the EO parameters can be obtained from the integrated system navigation solution. This process is referred to as Direct Georeferencing (DG). DG provides substantial benefits over the indirect determination method of estimating the EO parameters from conventional Aerial Triangulation (AT) techniques using a block of images with a sufficient number of known control points. These benefits include the ability to map remote and inaccessible regions, and by replacing tie point measurements/matching and AT, significant cost-savings can be obtained for projects that do not require stereo models (such as projects with existing DEM or single image). The accuracy of DG, however, is limited by the accuracy attainable by the DGPS and any residual datum calibration errors. These can typically be as large as 10 cm RMSE, which is not sufficient for some large scale mapping applications. However, by combining the direct EO data a traditional block adjustment, AT techniques can be used to remove the residual errors in the solution. This technique is known as Integrated Sensor Orientation (ISO). It has several advantages over traditional AT, primarily because the stable geometry provided by direct EO can reduce the number of required GCP and tie-point to a minimum. At the same time, ISO provides an excellent tool for Quality Control/Quality Assurance (QC/QA) of the EO derived from a DG system. This paper examines the factors that determine the system performance for ISO. In addition, examples are given to illustrate the expected accuracy of an aerial mapping project using ISO under different qualities of DGPS/IMU data. Copyright ASPRS Numéro de notice : A2007-013 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.73.1.89 En ligne : https://doi.org/10.14358/PERS.73.1.89 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28379 [article]