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Correction of laser scanning intensity data: data and model-driven approaches / Bernhard Höfle in ISPRS Journal of photogrammetry and remote sensing, vol 62 n° 6 (November-December 2007)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 62 n° 6 (November-December 2007) . - pp 415 - 433 Titre : Correction of laser scanning intensity data: data and model-driven approaches Type de document : Article/Communication Auteurs : Bernhard Höfle, Auteur ; Norbert Pfeifer, Auteur Année de publication : 2007 Article en page(s) : pp 415 - 433 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] correction du signal [Termes IGN] intensité lumineuse [Termes IGN] réflectance de surface [Termes IGN] signal laser [Termes IGN] télémètre laser à balayage [Termes IGN] traitement du signal Résumé : (Auteur) Most airborne and terrestrial laser scanning systems additionally record the received signal intensity for each measurement. Multiple studies show the potential of this intensity value for a great variety of applications (e.g. strip adjustment, forestry, glaciology), but also state problems if using the original recorded values. Three main factors, a) spherical loss, b) topographic and c) atmospheric effects, influence the backscatter of the emitted laser power, which leads to a noticeably heterogeneous representation of the received power. This paper describes two different methods for correcting the laser scanning intensity data for these known influences resulting in a value proportional to the reflectance of the scanned surface. The first approach – data-driven correction – uses predefined homogeneous areas to empirically estimate the best parameters (least-squares adjustment) for a given global correction function accounting for all range-dependent influences. The second approach – model-driven correction – corrects each intensity independently based on the physical principle of radar systems. The evaluation of both methods, based on homogeneous reflecting areas acquired at different heights in different missions, indicates a clear reduction of intensity variation, to 1/3.5 of the original variation, and offsets between flight strips to 1/10. The presented correction methods establish a great potential for laser scanning intensity to be used for surface classification and multi-temporal analyses. Copyright ISPRS Numéro de notice : A2007-528 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2007.05.008 En ligne : https://doi.org/10.1016/j.isprsjprs.2007.05.008 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28891 [article]

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Bidirectional reflectance spectrometry of gravel at the Sjökulla test field / J. Peltoniemi in ISPRS Journal of photogrammetry and remote sensing, vol 62 n° 6 (November-December 2007)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 62 n° 6 (November-December 2007) . - pp 434 - 446 Titre : Bidirectional reflectance spectrometry of gravel at the Sjökulla test field Type de document : Article/Communication Auteurs : J. Peltoniemi, Auteur ; J. Piironen, Auteur ; et al., Auteur Année de publication : 2007 Article en page(s) : pp 434 - 446 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image [Termes IGN] analyse diachronique [Termes IGN] distribution du coefficient de réflexion bidirectionnelle BRDF [Termes IGN] étalonnage radiométrique [Termes IGN] étalonnage spectral [Termes IGN] gravier [Termes IGN] image aérienne [Termes IGN] test de performance Résumé : (Auteur) The Sjökulla test site is used for testing and calibrating aerial images. The permanent test field is made of four types of gravel (dark gabbro, grey granite, red granite, white limestone) in two sizes (diameters 8–16 mm and 4–8 mm) set in various patterns. The bidirectional reflection properties of the targets together with their temporal changes must be known in order to carry out radiometric and spectral evaluation and calibration. The bidirectional reflectance distribution functions (BRF) of the gravel have been measured several times in the test fields using portable field goniospectrometers belonging Finnish Geodetic Institute (FGI), and once using the European Goniometic Facility (EGO) of the Joint Research Centre (JRC) at Ispra, Italy. Detailed BRFs have been obtained, showing features typical to particulate media, e.g. a small bowl shape, strong backscattering, and smooth wavelength dependence. Temporal range measurements over several years show that the black gabbro and red granite are fairly stable, while the grey granite has changed somewhat over the years and the white limestone has experienced dramatic darkening effects, requiring action to be taken. The measured BRF data have increased the usability of the test field considerably. The results are also useful in the development and validation of scattering models for particulate media. The site has proved to be a good test bench for goniospectrometric instruments, too. Copyright ISPRS Numéro de notice : A2007-529 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2007.07.009 En ligne : https://doi.org/10.1016/j.isprsjprs.2007.07.009 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28892 [article]

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Remote sensing research issues of the national land use change program of China / Jixian Zhang in ISPRS Journal of photogrammetry and remote sensing, vol 62 n° 6 (November-December 2007)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 62 n° 6 (November-December 2007) . - pp 461 - 472 Titre : Remote sensing research issues of the national land use change program of China Type de document : Article/Communication Auteurs : Jixian Zhang, Auteur ; Y. Zhang, Auteur Année de publication : 2007 Article en page(s) : pp 461 - 472 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] agriculture [Termes IGN] aménagement du territoire [Termes IGN] Chine [Termes IGN] détection de changement [Termes IGN] développement agricole [Termes IGN] développement durable [Termes IGN] gestion de production [Termes IGN] traitement d'image [Termes IGN] urbanisation [Termes IGN] utilisation du sol Résumé : (Auteur) In 1999, the Ministry of Land and Resources (MLR) of China launched the National Land Use Change Program especially to monitor the scale and distribution of urban expansion and the decrease in cultivated land through remote sensing technology. This Program has been carried out annually and continuously for seven years since then and played an important role in the policy-making of MLR about land management and planning. This paper gives an overview about this Program and discusses several research issues. First, the remote sensing data sources and other ancillary data used in this Program are presented. The approaches for image preprocessing, i.e. radiometric normalization, image geometric rectification and image fusion are then introduced with an emphasis on the algorithm development for image registration. Second, land use change detection technique is the most critical and complex aspect of the Program. The methodologies for change detection using either bi-temporal image pair or one existing land use map and one remotely sensed image are detailed. Third, since the data of land use changes derived from remote sensing will be operationally used for local and central government, field validation and accuracy assessment are crucial to ensure the reliability of change detection results. The strategy of field work and the resulting accuracy evaluations is presented. The land use and change information derived from remotely sensed data has wide applications for land management, including land use database updating, verification of land use planning and monitoring of national high-tech parks. Last, suggestions on how to make full use of the images and change detection result, to improve the consistency of land use classification and to develop change detection algorithms for diverse and complex remote sensing data are given. Copyright ISPRS Numéro de notice : A2007-530 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2007.07.002 En ligne : https://doi.org/10.1016/j.isprsjprs.2007.07.002 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28893 [article]

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Despeckle and geographical feature extraction in SAR images by wavelet transform / Karunesh K. Gupta in ISPRS Journal of photogrammetry and remote sensing, vol 62 n° 6 (November-December 2007)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 62 n° 6 (November-December 2007) . - pp 473 - 484 Titre : Despeckle and geographical feature extraction in SAR images by wavelet transform Type de document : Article/Communication Auteurs : Karunesh K. Gupta, Auteur ; Rajiv Gupta, Auteur Année de publication : 2007 Article en page(s) : pp 473 - 484 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image radar et applications [Termes IGN] analyse multiéchelle [Termes IGN] détection automatique [Termes IGN] extraction de traits caractéristiques [Termes IGN] filtre de déchatoiement [Termes IGN] image radar moirée [Termes IGN] transformation en ondelettes Résumé : (Auteur) This paper presents a method to despeckle Synthetic Aperture Radar (SAR) image, and then extract geographical features in it. In this research work, speckle is reduced by multiscale analysis in wavelet domain. In terms of geographical feature preservation the result shows that the method is better compared to spatial domain filters, such as Lee, Kuan, Frost, Ehfrost, Median, Gamma filters. The geographical features such as roads, airport runways, rivers and other ribbon-like shape structures are detected by the new wavelet-based method as proposed by Yuan Yan Tang. Experimental results show that the proposed method extracts geographical features of different width as well as different gray levels. Copyright ISPRS Numéro de notice : A2007-531 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2007.06.001 En ligne : https://doi.org/10.1016/j.isprsjprs.2007.06.001 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28894 [article]

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