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Evaluation of SAR-optical imagery synthesis techniques in a complex coastal ecosystem / F.M. Henderson in Photogrammetric Engineering & Remote Sensing, PERS, vol 68 n° 8 (August 2002)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 68 n° 8 (August 2002) . - pp 839 - 846 Titre : Evaluation of SAR-optical imagery synthesis techniques in a complex coastal ecosystem Type de document : Article/Communication Auteurs : F.M. Henderson, Auteur ; R. Chasan, Auteur ; J. Portolese, Auteur ; T. Hart, Auteur Année de publication : 2002 Article en page(s) : pp 839 - 846 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] classification ascendante hiérarchique [Termes IGN] classification dirigée [Termes IGN] écosystème [Termes IGN] Etats-Unis [Termes IGN] image optique [Termes IGN] image radar [Termes IGN] littoral [Termes IGN] précision [Termes IGN] radar à antenne synthétique [Termes IGN] Thematic Mapper Résumé : (Auteur) Coastal areas comprise some of the world's most important and sensitive ecosystems. Although optical remote sensing systems have demonstrated an ability to map land cover in many coastal environments, spectral confusion has also been reported. The parameters of SAR imagery suggest that combinations of SAR and optical data may improve land-cover classification accuracy. Seven satellite SAR data sets were merged with TM data using four techniques. These were tested by classifying 11 upland and wetland land covers in a rapidly urbanizing coastal area of the northeast United States. Not all SABITM combinations bettered the accuracy obtained using TM data alone. In general, simple techniques improved accuracy more than did complex image merge methods. Although one SAR image proved superior overall, improvement in detection accuracy varied among individual land-cover categories and SAR data. The results point to the possible benefits of hierarchical-layered classifications. Numéro de notice : A2002-164 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans En ligne : https://www.asprs.org/wp-content/uploads/pers/2002journal/august/2002_aug_839-84 [...] Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22079 [article]

Effects of JPEG compression on the accuracy of photogrammetric point determination / Z. Li in Photogrammetric Engineering & Remote Sensing, PERS, vol 68 n° 8 (August 2002)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 68 n° 8 (August 2002) . - pp 847 - 853 Titre : Effects of JPEG compression on the accuracy of photogrammetric point determination Type de document : Article/Communication Auteurs : Z. Li, Auteur ; X. Yuan, Auteur ; K.W. Lam, Auteur Année de publication : 2002 Article en page(s) : pp 847 - 853 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes IGN] compensation par faisceaux [Termes IGN] compression d'image [Termes IGN] compression de données [Termes IGN] image numérisée [Termes IGN] photographie aérienne [Termes IGN] précision de localisation Résumé : (Auteur) An empirical investigation into the effects of JPEG compression on the accuracy of photogrammetric point determination (PPD) is described. A pair of black-and-white aerial photographs of a city, taken at a scale of 1:8000, was selected and scanned at a resolution of 25 m. Eighteen image points were measured with the ISDM module of an Intergraph digital photogrammetric workstation (DPW), and the bundle adjustment of a single model was performed using WuGAPSsGps (Wuhan GPSsupported bundle block adjustment software). In processing various JPEG compressed images with Q-factors from I to 100, the accuracy of the 3D coordinates of the pass points was assessed and compared with that obtained from the original images (i.e., without compression). The empirical results show that, when the compression ratios are under 10, the compressed image is near-lossless. In other words, the visual quality of JPEG compressed images is still excellent and the accuracy of manual image mensuration is essentially not influenced. However, no indication can be found from the results that a compression of 10 is the critical value or the optimum compression level for PPD. Indeed, it is clear that the degradation of accuracy in PPD is almost linear. Numéro de notice : A2002-165 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : sans En ligne : http://www.lsgi.polyu.edu.hk/staff/ZL.Li/papers_pdf/photogrammetric_eng_Rem_sen/ [...] Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22080 [article]