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A morphologically preserved multi-resolution TIN surface modeling and visualization method for virtual globes / Xianwei Zheng in ISPRS Journal of photogrammetry and remote sensing, vol 129 (July 2017)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 129 (July 2017) . - pp 41 - 54 Titre : A morphologically preserved multi-resolution TIN surface modeling and visualization method for virtual globes Type de document : Article/Communication Auteurs : Xianwei Zheng, Auteur ; Hanjiang Xiong, Auteur ; Jianya Gong, Auteur ; Linwei Yue, Auteur Année de publication : 2017 Article en page(s) : pp 41 - 54 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géomatique web [Termes IGN] analyse multiéchelle [Termes IGN] arbre quadratique [Termes IGN] globe virtuel [Termes IGN] représentation cartographique 3D [Termes IGN] représentation du relief [Termes IGN] tessellation [Termes IGN] Triangulated Irregular Network Résumé : (Auteur) Virtual globes play an important role in representing three-dimensional models of the Earth. To extend the functioning of a virtual globe beyond that of a “geobrowser”, the accuracy of the geospatial data in the processing and representation should be of special concern for the scientific analysis and evaluation. In this study, we propose a method for the processing of large-scale terrain data for virtual globe visualization and analysis. The proposed method aims to construct a morphologically preserved multi-resolution triangulated irregular network (TIN) pyramid for virtual globes to accurately represent the landscape surface and simultaneously satisfy the demands of applications at different scales. By introducing cartographic principles, the TIN model in each layer is controlled with a data quality standard to formulize its level of detail generation. A point-additive algorithm is used to iteratively construct the multi-resolution TIN pyramid. The extracted landscape features are also incorporated to constrain the TIN structure, thus preserving the basic morphological shapes of the terrain surface at different levels. During the iterative construction process, the TIN in each layer is seamlessly partitioned based on a virtual node structure, and tiled with a global quadtree structure. Finally, an adaptive tessellation approach is adopted to eliminate terrain cracks in the real-time out-of-core spherical terrain rendering. The experiments undertaken in this study confirmed that the proposed method performs well in multi-resolution terrain representation, and produces high-quality underlying data that satisfy the demands of scientific analysis and evaluation. Numéro de notice : A2017-346 Affiliation des auteurs : non IGN Thématique : GEOMATIQUE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2017.04.013 En ligne : https://dx.doi.org/10.1016/j.isprsjprs.2017.04.013 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85606 [article]

Exemplaires(3)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-2017071	RAB	Revue	Centre de documentation	En réserve L003	Disponible
081-2017073	DEP-EXM	Revue	LASTIG	Dépôt en unité	Exclu du prêt
081-2017072	DEP-EAF	Revue	Nancy	Dépôt en unité	Exclu du prêt

Robust point cloud classification based on multi-level semantic relationships for urban scenes / Qing Zhu in ISPRS Journal of photogrammetry and remote sensing, vol 129 (July 2017)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 129 (July 2017) . - pp 86 - 102 Titre : Robust point cloud classification based on multi-level semantic relationships for urban scenes Type de document : Article/Communication Auteurs : Qing Zhu, Auteur ; Yuan Li, Auteur ; Han Hu, Auteur ; Bo Wu, Auteur Année de publication : 2017 Article en page(s) : pp 86 - 102 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] champ aléatoire de Markov [Termes IGN] classification [Termes IGN] description multiniveau [Termes IGN] exploration de données géographiques [Termes IGN] relation sémantique [Termes IGN] semis de points [Termes IGN] voxel [Termes IGN] zone urbaine Résumé : (Auteur) The semantic classification of point clouds is a fundamental part of three-dimensional urban reconstruction. For datasets with high spatial resolution but significantly more noises, a general trend is to exploit more contexture information to surmount the decrease of discrimination of features for classification. However, previous works on adoption of contexture information are either too restrictive or only in a small region and in this paper, we propose a point cloud classification method based on multi-level semantic relationships, including point–homogeneity, supervoxel–adjacency and class–knowledge constraints, which is more versatile and incrementally propagate the classification cues from individual points to the object level and formulate them as a graphical model. The point–homogeneity constraint clusters points with similar geometric and radiometric properties into regular-shaped supervoxels that correspond to the vertices in the graphical model. The supervoxel–adjacency constraint contributes to the pairwise interactions by providing explicit adjacent relationships between supervoxels. The class–knowledge constraint operates at the object level based on semantic rules, guaranteeing the classification correctness of supervoxel clusters at that level. International Society of Photogrammetry and Remote Sensing (ISPRS) benchmark tests have shown that the proposed method achieves state-of-the-art performance with an average per-area completeness and correctness of 93.88% and 95.78%, respectively. The evaluation of classification of photogrammetric point clouds and DSM generated from aerial imagery confirms the method’s reliability in several challenging urban scenes. Numéro de notice : A2017-347 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2017.04.022 En ligne : https://dx.doi.org/10.1016/j.isprsjprs.2017.04.022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85611 [article]

Exemplaires(3)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-2017071	RAB	Revue	Centre de documentation	En réserve L003	Disponible
081-2017073	DEP-EXM	Revue	LASTIG	Dépôt en unité	Exclu du prêt
081-2017072	DEP-EAF	Revue	Nancy	Dépôt en unité	Exclu du prêt

WREP : A wavelet-based technique for extracting the red edge position from reflectance spectra for estimating leaf and canopy chlorophyll contents of cereal crops / Dong Li in ISPRS Journal of photogrammetry and remote sensing, vol 129 (July 2017)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 129 (July 2017) . - pp 103 - 117 Titre : WREP : A wavelet-based technique for extracting the red edge position from reflectance spectra for estimating leaf and canopy chlorophyll contents of cereal crops Type de document : Article/Communication Auteurs : Dong Li, Auteur ; Tao Cheng, Auteur ; Kai Zhou, Auteur Année de publication : 2017 Article en page(s) : pp 103 - 117 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Applications de télédétection [Termes IGN] bande rouge [Termes IGN] canopée [Termes IGN] céréales [Termes IGN] cultures [Termes IGN] ondelette [Termes IGN] rayonnement proche infrarouge [Termes IGN] réflectance spectrale [Termes IGN] teneur en chlorophylle des feuilles [Termes IGN] transformation en ondelettes Résumé : (Auteur) Red edge position (REP), defined as the wavelength of the inflexion point in the red edge region (680–760 nm) of the reflectance spectrum, has been widely used to estimate foliar chlorophyll content from reflectance spectra. A number of techniques have been developed for REP extraction in the past three decades, but most of them require data-specific parameterization and the consistence of their performance from leaf to canopy levels remains poorly understood. In this study, we propose a new technique (WREP) to extract REPs based on the application of continuous wavelet transform to reflectance spectra. The REP is determined by the zero-crossing wavelength in the red edge region of a wavelet transformed spectrum for a number of scales of wavelet decomposition. The new technique is simple to implement and requires no parameterization from the user as long as continuous wavelet transforms are applied to reflectance spectra. Its performance was evaluated for estimating leaf chlorophyll content (LCC) and canopy chlorophyll content (CCC) of cereal crops (i.e. rice and wheat) and compared with traditional techniques including linear interpolation, linear extrapolation, polynomial fitting and inverted Gaussian. Our results demonstrated that WREP obtained the best estimation accuracy for both LCC and CCC as compared to traditional techniques. High scales of wavelet decomposition were favorable for the estimation of CCC and low scales for the estimation of LCC. The difference in optimal scale reveals the underlying mechanism of signature transfer from leaf to canopy levels. In addition, crop-specific models were required for the estimation of CCC over the full range. However, a common model could be built with the REPs extracted with Scale 5 of the WREP technique for wheat and rice crops when CCC was less than 2 g/m2 (R2 = 0.73, RMSE = 0.26 g/m2). This insensitivity of WREP to crop type indicates the potential for aerial mapping of chlorophyll content between growth seasons of cereal crops. The new REP extraction technique provides us a new insight for understanding the spectral changes in the red edge region in response to chlorophyll variation from leaf to canopy levels. Numéro de notice : A2017-348 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2017.04.024 En ligne : https://dx.doi.org/10.1016/j.isprsjprs.2017.04.024 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85616 [article]

Exemplaires(3)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-2017071	RAB	Revue	Centre de documentation	En réserve L003	Disponible
081-2017073	DEP-EXM	Revue	LASTIG	Dépôt en unité	Exclu du prêt
081-2017072	DEP-EAF	Revue	Nancy	Dépôt en unité	Exclu du prêt

Gold – A novel deconvolution algorithm with optimization for waveform LiDAR processing / Tan Zhou in ISPRS Journal of photogrammetry and remote sensing, vol 129 (July 2017)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 129 (July 2017) . - pp 131 - 150 Titre : Gold – A novel deconvolution algorithm with optimization for waveform LiDAR processing Type de document : Article/Communication Auteurs : Tan Zhou, Auteur ; Sorin C. Popescu, Auteur ; Keith Krause, Auteur ; et al., Auteur Année de publication : 2017 Article en page(s) : pp 131 - 150 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] analyse comparative [Termes IGN] déconvolution [Termes IGN] forme d'onde [Termes IGN] optimisation (mathématiques) [Termes IGN] traitement du signal Résumé : (Auteur) Waveform Light Detection and Ranging (LiDAR) data have advantages over discrete-return LiDAR data in accurately characterizing vegetation structure. However, we lack a comprehensive understanding of waveform data processing approaches under different topography and vegetation conditions. The objective of this paper is to highlight a novel deconvolution algorithm, the Gold algorithm, for processing waveform LiDAR data with optimal deconvolution parameters. Further, we present a comparative study of waveform processing methods to provide insight into selecting an approach for a given combination of vegetation and terrain characteristics. We employed two waveform processing methods: (1) direct decomposition, (2) deconvolution and decomposition. In method two, we utilized two deconvolution algorithms – the Richardson-Lucy (RL) algorithm and the Gold algorithm. The comprehensive and quantitative comparisons were conducted in terms of the number of detected echoes, position accuracy, the bias of the end products (such as digital terrain model (DTM) and canopy height model (CHM)) from the corresponding reference data, along with parameter uncertainty for these end products obtained from different methods. This study was conducted at three study sites that include diverse ecological regions, vegetation and elevation gradients. Results demonstrate that two deconvolution algorithms are sensitive to the pre-processing steps of input data. The deconvolution and decomposition method is more capable of detecting hidden echoes with a lower false echo detection rate, especially for the Gold algorithm. Compared to the reference data, all approaches generate satisfactory accuracy assessment results with small mean spatial difference ( Numéro de notice : A2017-349 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2017.04.021 En ligne : https://dx.doi.org/10.1016/j.isprsjprs.2017.04.021 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=85622 [article]

Exemplaires(3)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
081-2017071	RAB	Revue	Centre de documentation	En réserve L003	Disponible
081-2017073	DEP-EXM	Revue	LASTIG	Dépôt en unité	Exclu du prêt
081-2017072	DEP-EAF	Revue	Nancy	Dépôt en unité	Exclu du prêt