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Assessment of orthoimage and DEM derived from ZY-3 stereo image in Northeastern China / Y. Dong in Survey review, vol 48 n° 349 (July 2016)  

Public [article]  inSurvey review > vol 48 n° 349 (July 2016) . - pp 258 - 268 Titre : Assessment of orthoimage and DEM derived from ZY-3 stereo image in Northeastern China Type de document : Article/Communication Auteurs : Y. Dong, Auteur ; W. Cheng, Auteur ; Hoon Chang, Auteur ; et al., Auteur Année de publication : 2016 Article en page(s) : pp 258 - 268 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] Chine [Termes IGN] image ZiYuan-3 [Termes IGN] MNS ASTER [Termes IGN] modèle numérique de surface [Termes IGN] modèle par fonctions rationnelles [Termes IGN] modèle stéréoscopique [Termes IGN] orthoimage Résumé : (auteur) ZiYuan-3 (ZY-3, meaning Resource-3) is China's first civilian multispectral satellite with high-resolution stereo mapping capability. The along-track stereo images of ZY-3 allow the generation of digital elevation models (DEMs) for various mapping applications. This article evaluated the precision of the derived stereo DEM and orthoimages of ZY-3 data for a test site in Northeastern China. Pixel offset and GPS survey data were used to evaluate the image products. Orthoimages were derived by incorporating rational polynomial coefficients (RPCs) of the satellite orbits and the reference DEMs, including the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) global digital elevation model (GDEM) and ZY-3 stereo elevation model. The generations of orthoimages were categorised into four approaches depending on the RPCs, control points and/or reference DEMs used. When only the ASTER GDEM was used, the derived orthoimages of the forward and backward viewing sensors showed clear pixel offsets against the GPS check points (CKPs). For example, the offsets of the orthoimage derived using forward-looking image were 13·58 and 26·50 m, in x (easting) and y (northing) directions, respectively. These results also indicated that the pixel offset vectors between the forward and backward orthoimages was systematic which was caused by the error in the RPCs. The second and third approaches were to generate the ZY-3 stereo DEMs first, with and without the use of ground control points (GCPs), and then used the stereo DEMs to generate the orthoimages of the forward and backward looking images. The forth approach used both GCPs and ASTER GDEM to generate the orthoimages. The results showed the use of four GCPs in the process improved the accuracy of the orthoimages. Therefore, ZY-3 can deliver the DEM and orthoimage products to meet the accuracy requirement of the national 1 : 50 000 mapping with four well distributed GCPs. Numéro de notice : A2016-623 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1179/1752270615Y.0000000027 En ligne : https://doi.org/10.1179/1752270615Y.0000000027 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=81825 [article]

Using optical projection in close-range photogrammetry for 6DOF sensor positioning / B. Zheng in Photogrammetric Engineering & Remote Sensing, PERS, vol 79 n° 1 (January 2013)  

Public [article]  inPhotogrammetric Engineering & Remote Sensing, PERS > vol 79 n° 1 (January 2013) . - pp 79 - 86 Titre : Using optical projection in close-range photogrammetry for 6DOF sensor positioning Type de document : Article/Communication Auteurs : B. Zheng, Auteur ; Y. Dong, Auteur ; A. Davies, Auteur ; B. Mullany, Auteur ; E. Morse, Auteur Année de publication : 2013 Article en page(s) : pp 79 - 86 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie terrestre [Termes IGN] étalonnage d'instrument [Termes IGN] orientation du capteur [Termes IGN] photogrammétrie métrologique Résumé : (Auteur) A novel, low cost, non-contact, six degrees of freedom (DOF) measurement technique is proposed that enables real-time measurement of a small lightweight module's location. Straight forward applications of the proposed technique include robot calibration by installing the module to the end effector of a robot arm, and head-tracking in a typical virtual reality environment by attaching the module to a human head. The technique is based on a combination of photogrammetry and optical pattern projection. The module generates an optical pattern that is observable on the surrounding walls, and photogrammetry is used to measure the absolute coordinates of features in the projected optical pattern with respect to a defined global coordinate system. By combining these absolute coordinates with the known angular information of the optical projection beams, a minimization algorithm can be used to extract the absolute coordinates and angular orientation of the module itself. Experimental agreement of 1 to 5 parts in 103 was obtained by translating the module over 0.9 m and by rotating it through 60°. Numerical simulations were conducted to demonstrate that optimum design of the projected pattern gives a lower associated measurement uncertainty than is possible by direct photogrammetric measurement with traditional tie points. This paper documents the proof of principle and describes how the measurement can be further improved. Numéro de notice : A2013-007 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.14358/PERS.79.1.79 En ligne : https://doi.org/10.14358/PERS.79.1.79 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=32145 [article]