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Auteur Yilin Zhou
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Affiner la recherche Interroger des sources externesA two-step approach for the correction of rolling shutter distortion in UAV photogrammetry / Yilin Zhou in ISPRS Journal of photogrammetry and remote sensing, vol 160 (February 2020)
Titre : A two-step approach for the correction of rolling shutter distortion in UAV photogrammetry Type de document : Article/Communication Auteurs : Yilin Zhou Année de publication : 2020 Projets : 1-Pas de projet / Article en page(s) : pp 51 - 66 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] capteur aérien
[Termes IGN] compensation par faisceaux
[Termes IGN] correction
[Termes IGN] création de zone intermédiaire
[Termes IGN] distorsion d'image
[Termes IGN] étalonnage en vol
[Termes IGN] image captée par drone
[Termes IGN] MicMac
[Termes IGN] obturateur
[Termes IGN] photogrammétrie aérienneRésumé : (Auteur) The use of consumer grade unmanned aerial vehicles (UAV) is becoming more and more ubiquitous in photogrammetric applications. A large proportion of consumer grade UAVs are equipped with CMOS image sensor and rolling shutter. When imaging with a rolling shutter camera, the image sensor is exposed line by line, which can introduce additional distortions in image space since the UAV navigates at a relatively high speed during aerial acquisitions. In this paper, we propose (1) an approach to calibrate the readout time of rolling shutter camera, (2) a two-step method to correct the image distortion introduced by this effect. The two-step method makes assumption that during exposure, the change of camera orientation is negligible with respect to the change of camera position, which is often the case when camera is fixed on a stabilized mount. Firstly, the camera velocity is estimated from the results of an initial bundle block adjustment; then, one camera pose per scan-line of the image sensor is recovered and image observations are corrected. To evaluate the performance of the proposed method, four datasets of block and corridor configurations are acquired with the DJI Mavic 2 Pro and its original Hasselbald L1D-20c camera. The proposed method is implemented in MicMac, a free, open-source photogrammetric software; comparisons are carried out with other two mainstream software, AgiSoft MetaShape and Pix4D, which also have the functionality of rolling shutter effect correction. For block configuration datasets, the three software give comparable results. AgiSoft Metashape and Pix4D are sensitive to the flight configuration and encounter difficulties when processing datasets in corridor configurations. The proposed method shows good robustness both in block and corridor configurations, and is the only method that works in corridor configuration. After the application of the rolling shutter effect correction, the 3D accuracy is improved by 30–60% in block configuration and 15–25% in corridor configuration. A further improvement can be expected if a precise dating of image is available or if the camera positions can be directly extracted from GNSS data. Numéro de notice : A2020-018 Affiliation des auteurs : LASTIG MATIS+Ext (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2019.11.020 Date de publication en ligne : 16/12/2019 En ligne : https://doi.org/10.1016/j.isprsjprs.2019.11.020 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94456
in ISPRS Journal of photogrammetry and remote sensing > vol 160 (February 2020) . - pp 51 - 66[article]Exemplaires(3)
Code-barres Cote Support Localisation Section Disponibilité 081-2020021 RAB Revue Centre de documentation En réserve L003 Disponible 081-2020023 DEP-RECP Revue LASTIG Dépôt en unité Exclu du prêt 081-2020022 DEP-RECF Revue Nancy Dépôt en unité Exclu du prêt
Titre : Simulation and analysis of photogrammetric UAV image blocks - Influence of camera calibration error Type de document : Article/Communication Auteurs : Yilin Zhou Année de publication : 2020 Projets : 1-Pas de projet / Article en page(s) : n° 22 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] bloc d'images
[Termes IGN] compensation par faisceaux
[Termes IGN] effet thermique
[Termes IGN] étalonnage de chambre métrique
[Termes IGN] image captée par drone
[Termes IGN] obturateur
[Termes IGN] prise de vue aérienneRésumé : (auteur) Unmanned aerial vehicles (UAV) are increasingly used for topographic mapping. The camera calibration for UAV image blocks can be performed a priori or during the bundle block adjustment (self-calibration). For an area of interest with flat scene and corridor configuration, the focal length of camera is highly correlated with the height of the camera. Furthermore, systematic errors of camera calibration accumulate on the longer dimension and cause deformation. Therefore, special precautions must be taken when estimating camera calibration parameters. In order to better investigate the impact of camera calibration errors, a synthetic, error-free aerial image block is generated to simulate several issues of interest. Firstly, the erroneous focal length in the case of camera pre-calibration is studied. Nadir images are not able to prevent camera poses from drifting to compensate for the erroneous focal length, whereas the inclusion of oblique images brings significant improvement. Secondly, the case where the focal length varies gradually (e.g., when the camera subject to temperature changes) is investigated. The neglect of this phenomenon can substantially degrade the 3D measurement accuracy. Different flight configurations and flight orders are analyzed, the combination of oblique and nadir images shows better performance. At last, the rolling shutter effect is investigated. The influence of camera rotational motion on the final accuracy is negligible compared to that of the translational motion. The acquisition configurations investigated are not able to mitigate the degradation introduced by the rolling shutter effect. Other solutions such as correcting image measurements or including camera motion parameters in the bundle block adjustment should be exploited. Numéro de notice : A2020-415 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.3390/rs12010022 Date de publication en ligne : 19/12/2019 En ligne : https://doi.org/10.3390/rs12010022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=95503
in Remote sensing > vol 12 n° 1 (January 2020) . - n° 22[article]
Titre : Simulation and analysis of photogrammetric UAV image blocks: influence of camera calibration error Type de document : Article/Communication Auteurs : Yilin Zhou Année de publication : 2019 Projets : 1-Pas de projet / Conférence : ISPRS 2019, Geospatial Week 10/06/2019 14/06/2019 Enschede Pays-Bas ISPRS OA Annals Article en page(s) : pp 195 - 200 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] bloc d'images
[Termes IGN] compensation par faisceaux
[Termes IGN] effet thermique
[Termes IGN] erreur systématique
[Termes IGN] estimation de pose
[Termes IGN] étalonnage de chambre métrique
[Termes IGN] étalonnage en vol
[Termes IGN] image aérienne oblique
[Termes IGN] image captée par drone
[Termes IGN] longueur focale
[Termes IGN] photogrammétrie aérienne
[Termes IGN] point d'appui
[Termes IGN] points homologuesRésumé : (auteur) Unmanned aerial vehicles (UAV) are increasingly used for topographic mapping. The camera calibration for UAV image blocks can be performed a priori or during the bundle block adjustment (self-calibration). For an area of interest with flat, corridor configuration, the focal length of camera is highly correlated with the height of camera. Furthermore, systematic errors of camera calibration accumulate on the longer dimension and cause deformation. Therefore, special precautions must be taken when estimating camera calibration parameters. In this paper, a simulated, error-free aerial image block is generated. error is then added on camera calibration and given as initial solution to bundle block adjustment. Depending on the nature of the error and the investigation purpose, camera calibration parameters are either fixed or re-estimated during the bundle block adjustment. The objective is to investigate how certain errors in the camera calibration impact the accuracy of 3D measurement without the influence of other errors. All experiments are carried out with Fraser camera calibration model being employed. When adopting a proper flight configuration, an error on focal length for the initial camera calibration can be corrected almost entirely during bundle block adjustment. For the case where an erroneous focal length is given for pre-calibration and not re-estimated, the presence of oblique images limits the drift on camera height hence gives better camera pose estimation. Other than that, the error on focal length when neglecting its variation during the acquisition (e.g., due to camera temperature increase) is also investigated; a bowl effect is observed when one focal length is given in camera pre-calibration to the whole image block. At last, a local error is added in image space to simulate camera flaws; this type of error is more difficult to be corrected with the Fraser camera model and the accuracy of 3D measurement degrades substantially. Numéro de notice : A2019-591 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprs-annals-IV-2-W5-195-2019 Date de publication en ligne : 29/05/2019 En ligne : https://doi.org/10.5194/isprs-annals-IV-2-W5-195-2019 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94551
in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol IV-2/W5 (May 2019) . - pp 195 - 200[article]
Titre : Improvement of photogrammetric accuracy by modeling and correcting the thermal effect on camera calibration Type de document : Article/Communication Auteurs : Mehdi Daakir Année de publication : 2019 Projets : 1-Pas de projet / Article en page(s) : pp 142 - 156 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] CamLight
[Termes IGN] déformation d'image
[Termes IGN] détecteur CMOS
[Termes IGN] effet thermique
[Termes IGN] étalonnage de capteur (imagerie)
[Termes IGN] image captée par drone
[Termes IGN] modèle géométrique de prise de vue
[Termes IGN] photogrammétrie métrologiqueRésumé : (Auteur) This paper presents a new method for improving the geometric accuracy of photogrammetric reconstruction by modeling and correcting the thermal effect on camera image sensor. The objective is to verify that when the temperature of image sensor varies during the acquisition, image deformation induced by the temperature change is quantifiable, modelisable and correctable. A temperature sensor integrated in the camera enables the measurement of image sensor temperature at exposure. It is therefore natural and appropriate to take this effect into account and to finally model and correct it after a calibration step. Nowadays, in cartography applications performed with UAV, the frame rate of acquisitions is continuously increasing. A high frame rate over a long acquisition time can result in an important temperature increase of the image sensor and thus introduces image deformations. The correction of the above-mentioned effect can improve the measurement accuracy. We present three methods to calibrate the thermal effect and experiments on two datasets are carried out to verify the improvement in terms of the photogrammetric accuracy. Numéro de notice : A2019-072 Affiliation des auteurs : LASTIG LOEMI+Ext (2012-2019) Autre URL associée : vers HAL Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2018.12.012 Date de publication en ligne : 04/01/2019 En ligne : https://doi.org/10.1016/j.isprsjprs.2018.12.012 Format de la ressource électronique : URL Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92159
in ISPRS Journal of photogrammetry and remote sensing > vol 148 (February 2019) . - pp 142 - 156[article]Exemplaires(3)
Code-barres Cote Support Localisation Section Disponibilité 081-2019021 RAB Revue Centre de documentation En réserve L003 Disponible 081-2019023 DEP-RECP Revue LASTIG Dépôt en unité Exclu du prêt 081-2019022 DEP-RECF Revue Nancy Dépôt en unité Exclu du prêt 100% automatic metrology with UAV photogrammetry and embedded GPS, and its application in dike monitoring / Yilin Zhou (2019)
Titre : 100% automatic metrology with UAV photogrammetry and embedded GPS, and its application in dike monitoring Titre original : Métrologie 100 % automatique par photogrammétrie aéroportée légère et GPS de précision permanent et embarqué : application au suivi de digues Type de document : Thèse/HDR Auteurs : Yilin Zhou Editeur : Champs/Marne : Université Paris-Est Marne-la-Vallée UPEM Année de publication : 2019 Importance : 181 p. Format : 21 x 30 cm Note générale : bibliographie
Thèse de Doctorat de l'Université Paris-Est, Sciences et Technologies de l'Information GéographiqueLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] angle nadiral
[Termes IGN] digue
[Termes IGN] données GNSS
[Termes IGN] effet thermique
[Termes IGN] étalonnage de chambre métrique
[Termes IGN] image aérienne
[Termes IGN] image aérienne oblique
[Termes IGN] image captée par drone
[Termes IGN] modélisation 3D
[Termes IGN] obturateur
[Termes IGN] photogrammétrie métrologique
[Termes IGN] point d'appui
[Termes IGN] réseau fluvialIndex. décimale : THESE Thèses et HDR Résumé : (auteur) The development of unmanned aerial vehicle (UAV) platform makes it nowadays a valuable source of data for inspection, surveillance, mapping and 3D modeling issues. UAV photogrammetry opens various new applications in close-range aerial domain and introduces a low-cost alternative to classical manned vehicle photogrammetry. Corridor mapping, one of the fields with substantial importance for UAV photo-grarnmetry, is largely demanded in the surveillance and management of infrastructure assets — highways, railways, waterways and pipelines. Due to the special geometry of the scene, corridor mapping is one case that needs taking precautions. Errors accumu-late easily on the longer dimension of the scene and a bowl effect is often observed; the flatness of the scene introduces strong correlations between parameters to be determi-ned, these two factors together, make it more difficult to obtain high accuracy results in corridor configuration than in classical ones. This thesis is a research project initiated by the CNR, a river concessionary, which has the responsibility of the maintenance and surveillance of its hydraulic facilities, more particularly the dikes. The objective is to apply UAV photogrammetry, which is faster, cheaper and offers a 3D dense reconstruction of the scene, to the monitoring of dikes. While maintaining a high surveying accuracy, a reduced field work, i.e. the number of ground control points (GCPs) is expected. In the first place, simulations are carried out to gain an insight of several problems of corridor mapping that impact the final accuracy. Then, thorough investigations are conducted on three aspects that interest us the most. The first study focuses on the aerial acquisition geometry, discussions are given on the influence of oblique images, nadir images of different flight heights as well as the possibility of an in-flight camera calibration and its application on unfavourable acquisition geometry. The second study aims to improve the acquisition performance for high-end metric cameras. The image deformation introduced by camera temperature variation is investigated and modelled. A method for the correction of this thermal effect is proposed, its performance is eva-luated on both terrestrial and aerial datasets of corridor configuration. The last study interests in the rolling shutter effect for consumer-grade cameras, which is commonly seen in UAV platforms on the market. Two methods are presented to calibrate the camera readout time, a property that is often not given by camera manufacturers. A two-step method is proposed for the correction of rolling shutter effect, its performance is evaluated in both block and corridor configurations. Note de contenu : 1- Introduction en français
2- Introduction
3- State of the art
4- Simulation and analysis
5- Study of aerial acquisition geometry
6- Study of thermal effect
7- Study of rolling shutter effect
8- Conclusion and perspectiveNuméro de notice : 25522 Affiliation des auteurs : LASTIG LOEMI (2012-2019) Thématique : IMAGERIE Nature : Thèse française Note de thèse : Thèse de Doctorat : Géophysique : Paris-Est : 2019 Organisme de stage : LaSTIG (IGN) nature-HAL : Thèse DOI : sans Date de publication en ligne : 11/02/2020 En ligne : https://hal.science/tel-02474315v2/ Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=94383 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 25522-01 THESE Livre Centre de documentation Thèses Disponible PermalinkPermalink
