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Small-footprint laser scanning simulator for system validation, error assessment, and algorithm development / Antero Kukko in Photogrammetric Engineering & Remote Sensing, PERS, vol 75 n° 10 (October 2009)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 75 n° 10 (October 2009) . - pp 1177 - 1189 Titre : Small-footprint laser scanning simulator for system validation, error assessment, and algorithm development Type de document : Article/Communication Auteurs : Antero Kukko, Auteur ; Juha Hyyppä, Auteur Année de publication : 2009 Article en page(s) : pp 1177 - 1189 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] classification orientée objet [Termes IGN] détection de changement [Termes IGN] données lidar [Termes IGN] erreur systématique [Termes IGN] faisceau laser [Termes IGN] hauteur des arbres [Termes IGN] instrumentation Toposys [Termes IGN] modèle de simulation [Termes IGN] précision décimétrique [Termes IGN] semis de points [Termes IGN] signal laser [Termes IGN] télémétrie laser aéroporté Résumé : (Auteur) Airborne lidar systems have come to be extensively used in photogrammetry and mapping sciences. In this paper, a high-quality simulation approach and methods of smallfootprint lidar processing are presented and discussed, validated for tree height estimation, and demonstrated for scanning geometry effects analysis and mobile mapping. The simulation method implemented combines both spatial and radiometric components to produce realistic waveform and point cloud data for system performance analysis and for algorithm development for lidar data processing and mapping purposes. Waveform data generated by the simulator were shown to demonstrate the possibilities of such an approach in system and data verification. As the related empirical data are insufficient for effective research and exploitation in mapping purposes at the moment, the simulated waveform data are needed. A tree location accuracy of 15 cm and tree height underestimation of 0.33 m was found using the simulation model for the TopEye Mk II laser scanner, compared to the artificial forest model reference data. Modeling of light interaction on object surfaces and characteristics of scanning systems provide an opportunity to simulate laser data acquisition of well-defined objects under controlled conditions. By eliminating different sources of error case-by-case, we can improve the knowledge obtained merely from the experimental studies. Data validation in the scanning geometry simulations was carried out by comparing the simulated first echo data to the environment model and, separately, to the first echo data from an independent TopoSys II flight strip that was not used for the environment model computation. The mean differences reveal that the simulator slightly overestimates the object elevations. Deviation between the real TopoSys point cloud and the environmental model was 2 to 3 times larger than that obtained for the simulated Optech and TopoSys data sets. We believe that the developed simulation and modeling is an efficient tool for determining the most reasonable set of flight parameters for any current mapping task, for analyzing change detection possibilities of repeated laser surveys, and for studying and verifying future lidar systems and concepts. However, this requires high-quality modeling of the system and extensive knowledge of the interaction between the laser beam and the object, which should be further developed in the coming years. Copyright ASPRS Numéro de notice : A2009-419 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.75.10.1177 En ligne : https://doi.org/10.14358/PERS.75.10.1177 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30050 [article]

A Wavelet and IHS integration method to fuse high resolution SAR with moderate resolution multispectral images / G. Hong in Photogrammetric Engineering & Remote Sensing, PERS, vol 75 n° 10 (October 2009)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 75 n° 10 (October 2009) . - pp 1213 - 1223 Titre : A Wavelet and IHS integration method to fuse high resolution SAR with moderate resolution multispectral images Type de document : Article/Communication Auteurs : G. Hong, Auteur ; Y. Zhang, Auteur ; J. Bryan Mercer, Auteur Année de publication : 2009 Article en page(s) : pp 1213 - 1223 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image mixte [Termes IGN] fusion d'images [Termes IGN] image à haute résolution [Termes IGN] image à très haute résolution [Termes IGN] image Landsat-TM [Termes IGN] image multibande [Termes IGN] image radar moirée [Termes IGN] image Radarsat [Termes IGN] précision millimétrique [Termes IGN] résolution multiple [Termes IGN] transformation en ondelettes [Termes IGN] transformation intensité-teinte-saturation Résumé : (Auteur) Synthetic aperture radar (SAR) imaging can be a feasible alternative or a complement to traditional optical remote sensing techniques because it does not depend on solar illumination and weather conditions. The high spatial resolution of SAR, such as the Intermap STAR-3i airborne SAR image with 1.25 m spatial resolution, makes it applicable for high spatial resolution mapping purposes. However, difficulties sometimes exist in the interpretation of SAR images. Image fusion presents an alternative to improve the interpretability of SAR images by fusing the color information from moderate spatial resolution multispectral (MS) images. In this paper, a new fusion method based on the integration of wavelet transform and IHS (Intensity, Hue, and Saturation) transform is proposed for SAR and MS fusion to maintain the spectral content of the original MS image while retaining the spatial detail of the high-resolution SAR image. Three data sets are used to evaluate the proposed fusion method: two sets are airborne SAR images with MS images at different spatial resolutions; the other set is a Radarsat image with a Landsat TM image. The fusion results are evaluated visually and statistically. The evaluation shows that successful results are achieved in the fusion of all SAR and MS images from a variety of sensors with significant spatial and spectral variations by using the proposed image fusion method. Numéro de notice : A2009-420 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.75.10.1213 En ligne : https://doi.org/10.14358/PERS.75.10.1213 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30051 [article]