Centre de documentation
scientifique

Minimising algorithm-induced artefacts in true ortho-image generation: a direct method implemented in the vector domain / Y. Sheng in Photogrammetric record, vol 22 n° 118 (June - August 2007)  

Public [article]  inPhotogrammetric record > vol 22 n° 118 (June - August 2007) . - pp 151 - 163 Titre : Minimising algorithm-induced artefacts in true ortho-image generation: a direct method implemented in the vector domain Type de document : Article/Communication Auteurs : Y. Sheng, Auteur Année de publication : 2007 Article en page(s) : pp 151 - 163 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] artefact [Termes IGN] détection de partie cachée [Termes IGN] données vectorielles [Termes IGN] orthoimage intégrale Résumé : (Auteur) True ortho-images are generated from perspective images with both object and terrain displacement distortion corrected and with occlusions removed. However, widely used algorithms based on a Z-buffer have drawbacks and may result in artefacts in the generated ortho-images. This paper analyses the artefacts induced by Z-buffer algorithms in true ortho-image generation, and proposes a vector-based method to avoid algorithm-induced artefacts. The proposed method treats a perspective image pixel as a square patch instead of an image pixel point, and generates ortho-images in the vector domain. Under the vector implementation, occlusion detection is a simple process, and image resampling becomes a straightforward procedure. Most importantly, this method can minimise artefacts in the ortho-images so generated. Copyright RS&PS + Blackwell Publishing Numéro de notice : A2007-365 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2007.00425.x En ligne : https://doi.org/10.1111/j.1477-9730.2007.00425.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28728 [article]

Exemplaires(1)

Code-barres	Cote	Support	Localisation	Section	Disponibilité
106-07021	RAB	Revue	Centre de documentation	En réserve L003	Disponible

True ortho-image production for forested areas from large-scale aerial photographs / Y. Sheng in Photogrammetric Engineering & Remote Sensing, PERS, vol 69 n° 3 (March 2003)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 69 n° 3 (March 2003) . - pp 259 - 266 Titre : True ortho-image production for forested areas from large-scale aerial photographs Type de document : Article/Communication Auteurs : Y. Sheng, Auteur ; P. Gong, Auteur ; Gregory S. Biging, Auteur Année de publication : 2003 Article en page(s) : pp 259 - 266 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Orthophotographie, orthoimage [Termes IGN] correction des ombres [Termes IGN] couvert forestier [Termes IGN] déformation d'image [Termes IGN] dévers [Termes IGN] forêt [Termes IGN] modèle numérique de surface [Termes IGN] objet géographique 3D [Termes IGN] orthoimage [Termes IGN] orthoimage intégrale [Termes IGN] photographie à grande échelle [Termes IGN] photographie aérienne Résumé : (Auteur) An orthophoto is a fundamental information source in forestry. Orthophoto production is usally based on digital elevation models (DEM) ; however, the elevations of 3D objects suchs as buildings and trees, which are visible in large-scale photos, are not included in DEMs. Recently initiated "true orthophoto" generation has been dedicated to urban scenes, removing the displacement caused by both the terrain and buildings. This paper reports an effort on reducing occlusion and distortion caused by trees in true orthoimage generation for forested areas. Canopy surface models (CMS) depicting both the terrain and tree surfaces were used in forest orthoimage production. Z-buffer techniques were incorporated into indirect orthoimage production to remove occlusion. An angle-based strategy was applied to composite multi-occular images. The proposed techniques were applied in the generation of high-resolution orthoimages of redwood stand with 1:2 400-scale aerial photos. Numéro de notice : A2003-029 Affiliation des auteurs : non IGN Thématique : FORET/IMAGERIE Nature : Article DOI : 10.14358/PERS.69.3.259 En ligne : https://doi.org/10.14358/PERS.69.3.259 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=22326 [article]