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3D change detection using adaptive thresholds based on local point cloud density / Dan Liu in ISPRS International journal of geo-information, vol 10 n° 3 (March 2021)  

Public [article]  inISPRS International journal of geo-information > vol 10 n° 3 (March 2021) . - n° 127 Titre : 3D change detection using adaptive thresholds based on local point cloud density Type de document : Article/Communication Auteurs : Dan Liu, Auteur ; Dajun Li, Auteur ; Meizhen Wang, Auteur ; et al., Auteur Année de publication : 2021 Article en page(s) : n° 127 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] classification barycentrique [Termes IGN] densité des points [Termes IGN] détection de changement [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] MNS lidar [Termes IGN] scène urbaine [Termes IGN] semis de points [Termes IGN] seuillage de points Résumé : (auteur) In recent years, because of highly developed LiDAR (Light Detection and Ranging) technologies, there has been increasing demand for 3D change detection in urban monitoring, urban model updating, and disaster assessment. In order to improve the effectiveness of 3D change detection based on point clouds, an approach for 3D change detection using point-based comparison is presented in this paper. To avoid density variation in point clouds, adaptive thresholds are calculated through the k-neighboring average distance and the local point cloud density. A series of experiments for quantitative evaluation is performed. In the experiments, the influencing factors including threshold, registration error, and neighboring number of 3D change detection are discussed and analyzed. The results of the experiments demonstrate that the approach using adaptive thresholds based on local point cloud density are effective and suitable. Numéro de notice : A2021-231 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/ijgi10030127 Date de publication en ligne : 02/03/2021 En ligne : https://doi.org/10.3390/ijgi10030127 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=97222 [article]

Camera self-calibration with lens distortion from a single image / Dan Liu in Photogrammetric Engineering & Remote Sensing, PERS, vol 82 n° 5 (May 2016)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 82 n° 5 (May 2016) . - pp 325 - 334 Titre : Camera self-calibration with lens distortion from a single image Type de document : Article/Communication Auteurs : Dan Liu, Auteur ; Xuejun Liu, Auteur ; Meizhen Wang, Auteur Année de publication : 2016 Article en page(s) : pp 325 - 334 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] auto-étalonnage [Termes IGN] contrainte géométrique [Termes IGN] étalonnage de capteur (imagerie) [Termes IGN] photogrammétrie terrestre Résumé : (Auteur) This paper presents an effective approach for self-calibration with lens distortion using a single image combined with geometric constraints including vanishing points and ellipses. To improve the accuracy of self-calibration, radial distortion and distortion center are included in the calibration procedure. First, assuming image center as the symmetric center, the first radial distortion coefficient and vanishing points are simultaneously optimized from line segments in the image. Second, by utilizing the optimized vanishing points and extracted ellipse, principal distance and principal point are estimated. Last, distortion center is set as the current calculated principal point, and the above steps are then repeated until the principal point reaches a stable solution. Extensive quantitative and qualitative studies of the approach are performed. The experiments pertaining to simulated and real images demonstrate that the approach is effective and suitable and that the approach obtains satisfactory results. Numéro de notice : A2016-409 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.82.5.325 En ligne : http://dx.doi.org/10.14358/PERS.82.5.325 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81274 [article]