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Implementation of a real-time stacking algorithm in a photogrammetric digital camera for UAVs / Ahmad Audi (2017)
Titre : Implementation of a real-time stacking algorithm in a photogrammetric digital camera for UAVs Type de document : Article/Communication Auteurs : Ahmad Audi , Auteur ; Marc Pierrot-Deseilligny , Auteur ; Christophe Meynard , Auteur ; Christian Thom , Auteur Editeur : International Society for Photogrammetry and Remote Sensing ISPRS Année de publication : 2017 Collection : International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, ISSN 1682-1750 num. 42-2/W6 Conférence : ISPRS 2017, International Conference on Unmanned Aerial Vehicles in Geomatics 04/09/2017 07/09/2017 Bonn Allemagne ISPRS OA Archives Importance : pp 13 - 19 Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] chambre métrique
[Termes IGN] drone
[Termes IGN] flou
[Termes IGN] GPS-INS
[Termes IGN] implémentation (informatique)
[Termes IGN] points homologues
[Termes IGN] rééchantillonnage
[Termes IGN] rotation d'objetRésumé : (auteur) In the recent years, unmanned aerial vehicles (UAVs) have become an interesting tool in aerial photography and photogrammetry activities. In this context, some applications (like cloudy sky surveys, narrow-spectral imagery and night-vision imagery) need a longexposure time where one of the main problems is the motion blur caused by the erratic camera movements during image acquisition. This paper describes an automatic real-time stacking algorithm which produces a high photogrammetric quality final composite image with an equivalent long-exposure time using several images acquired with short-exposure times. Our method is inspired by feature-based image registration technique. The algorithm is implemented on the light-weight IGN camera, which has an IMU sensor and a SoC/FPGA. To obtain the correct parameters for the resampling of images, the presented method accurately estimates the geometrical relation between the first and the Nth image, taking into account the internal parameters and the distortion of the camera. Features are detected in the first image by the FAST detector, than homologous points on other images are obtained by template matching aided by the IMU sensors. The SoC/FPGA in the camera is used to speed up time-consuming parts of the algorithm such as features detection and images resampling in order to achieve a real-time performance as we want to write only the resulting final image to save bandwidth on the storage device. The paper includes a detailed description of the implemented algorithm, resource usage summary, resulting processing time, resulting images, as well as block diagrams of the described architecture. The resulting stacked image obtained on real surveys doesn’t seem visually impaired. Timing results demonstrate that our algorithm can be used in real-time since its processing time is less than the writing time of an image in the storage device. An interesting by-product of this algorithm is the 3D rotation estimated by a photogrammetric method between poses, which can be used to recalibrate in real-time the gyrometers of the IMU. Numéro de notice : C2017-037 Affiliation des auteurs : LASTIG LOEMI (2012-2019) Thématique : IMAGERIE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.5194/isprs-archives-XLII-2-W6-13-2017 Date de publication en ligne : 23/08/2017 En ligne : https://doi.org/10.5194/isprs-archives-XLII-2-W6-13-2017 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91886
Titre : Instantaneous estimation of attitude from GNSS Type de document : Thèse/HDR Auteurs : Hendy Fitrian Suhandri, Auteur ; Alfred Kleusberg, Directeur de thèse ; Hasanuddin Zainal Abidin, Directeur de thèse Editeur : Stuttgart : University of Stuttgart Année de publication : 2017 Importance : 143 p. Format : 21 x 30 cm Note générale : Bibliographie
thesis accepted by the Faculty of Aerospace Engineering and Geodesy of the University of Stuttgart in partial fulfilment of the requirements for the degree of Doctor of Engineering Sciences (Dr.-Ing.)Langues : Anglais (eng) Descripteur : [Termes IGN] ambiguïté entière
[Termes IGN] angle d'Euler
[Termes IGN] double différence
[Termes IGN] filtre de Kalman
[Termes IGN] méthode des moindres carrés
[Termes IGN] modèle stochastique
[Termes IGN] orientation de véhicule
[Termes IGN] positionnement cinématique
[Termes IGN] positionnement par GNSS
[Termes IGN] récepteur GNSS
[Termes IGN] simple différence
[Vedettes matières IGN] Traitement de données GNSSRésumé : (auteur) The use of the Global Navigation Satellite System (GNSS) is widely spread from position determination to attitude determination of a platform in space. This system offers time invariant estimation position. Another thing that can be an advantage is that the flexibility to operate the GNSS receiver variants, from the low-cost until the high-performance GNSS receivers. In terms of attitude determination application at least three receivers are required to determine three spatial axes, where the cost-effective GNSS attitude determination systems can be constructed with today’s receiver technology. At the moment, however, algorithms are lacking which are fast and efficient enough to estimate the position angles without delay. For this reason, the present work deals with the development of algorithms for the attitude determination in space of a platform under the help of the "GNSS" Global Positioning System (GPS). The investigation through this work is classified into three sequential parts: The first part is the estimation of the optimal configuration of baseline array as well as the estimation of the integer ambiguity of carrier phase differences. The estimated integer ambiguity is then used to estimate the high precision baseline coordinates. The second part is to estimate the attitude of the platform in space by means of quaternion using batch process, and the last part is to improve the algorithm using a recursive algorithm for the kinematic application purpose. The precise attitude determination about three spatial axes is possible if at least three GNSS receivers with fixed baselines are used in particular array configurations. Assuming that the basic lengths of the baselines are known a priori, the attitude angles can be calculated via the combination of carrier phase and pseudorange observations. Since the carrier of the GPS signal is propagated in short-wave form, the measured phase differences are ambiguous. The multiples of the GPS signal phases together with the baseline lengths are therefore estimated and improved in a first step with the aid of the a priori baseline lengths information. The multiple-baseline float solution estimation method is used. However, the approach does not provide optimal results. Therefore, an alternative algorithm for the float solution is presented, which estimates the float solution by using the socalled the gradient based iterative method of the least-squares. It shows that method is able to give convergent estimate parameter. It is also shown here that the proposed method outperforms the conventional iterative least-squares in terms of iteration number and computational time. For instantaneous applications, the Least-squares AMBiguity Decorrelation Adjustment (LAMBDA) method is not optimal for fixing the integer multiples of the carrier phase differences for several baseline lengths. In addition, this method requires a high computational effort as soon as a larger number of baseline lines enter into the calculation. An improvement in this work is utilising the partial LAMBDA method, which only uses a subset of the integer multiples to be determined. This algorithm improves the determination of integer multiples and precise calculation of the baseline lengths. The advantages of this algorithm are discussed, and it is empirically demonstrated that the ambiguities are better resolved. Furthermore, the estimation of the attitude angles with the aid of quaternions is theoretically improved and analysed. Two processing strategies are investigated: the least-squares method and the Kalman Filter (KF) method. For the static case, the least-squares is applied and tested. Simulations show that the developed gradient based iterative method of the least-squares provides better estimates than the conventional adjustment methods. It is also shown that the number of iterations required is less and the computational time is reduced. This algorithm is not useful for kinematic applications where a fast sequence of results is required. A modified Extended Kalman Filter (EKF)-Like algorithm is used for kinematic applications. Experiments show that with this algorithm more stable quaternions can be calculated with fewer outliers than when they are determined by the least-squares method. All newly developed algorithms are theoretically analysed and subjected to extensive simulations and experimental kinematic tests in the field. Note de contenu : Introduction
1 - General mathematical model of GNSS positioning
2 - Multi-baseline GNSS estimation method
3 - GNSS based attitude determination
4 - Recursive attitude determination
5 - Experimental result of static and kinematic tests
6 - Summary, conclusion and future work suggestionNuméro de notice : 21574 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : Doctor thesis : Engineering sciences : Stuttgart : 2017 DOI : 10.18419/opus-9239 En ligne : http://dx.doi.org/10.18419/opus-9239 Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90576
Titre : Integrated sensor orientation on micro aerial vehicles Type de document : Thèse/HDR Auteurs : Martin Rehak, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2017 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 98 Importance : 210 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-44-4 Note générale : bibliographie
pour l'obtention du grade de docteur ès sciencesLangues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s)
[Termes IGN] compensation par faisceaux
[Termes IGN] couplage GNSS-INS
[Termes IGN] étalonnage d'instrument
[Termes IGN] modélisation géométrique de prise de vue
[Termes IGN] orientation du capteur intégrée
[Termes IGN] plan de volIndex. décimale : 35.10 Acquisition d'images Résumé : (auteur) Mapping with Micro Aerial Vehicles (MAVs whose weight does not exceed 5 kg) is gaining importance in applications, such as corridor mapping, road and pipeline inspections, or mapping of large areas with homogeneous surface structure, e.g. forest or agricultural fields. When cm-level accuracy is required, the classical approach of sensor orientation does not deliver satisfactory results unless a large number of ground control points (GCPs) is regularly distributed in the mapped area. This may not be a feasible method either due to the associated costs or terrain inaccessibility.
This thesis addresses such issues by presenting a development of MAV platforms with navigation and imaging sensors that are able to perform integrated sensor orientation (ISO). This method combines image measurements with GNSS or GNSS/IMU (Global Navigation Satellite System/Inertial Measurement Unit) observations. This innovative approach allows mapping with cm-level accuracy without the support of GCPs, even in geometrically challenging scenarios, such as corridors. The presented solution also helps in situations where automatic image observations cannot be generated, e.g. over water, sand, or other surfaces with low variations of texture.
The application of ISO to MAV photogrammetry is a novel solution and its implementation brings new engineering and research challenges due to a limited payload capacity and quality of employed sensors on-board. These challenges are addressed using traditional as well as novel methods of treating observations within the developed processing software. The capability of the constructed MAV platforms and processing tools is tested in real mapping scenarios. It is empirically confirmed that accurate aerial control combined with a state-of- the-art calibration and processing can deliver cm-level ground accuracy, even in the most demanding projects.
This thesis also presents an innovative way of mission planning in challenging environments. Indeed, a thorough pre-flight analysis is important not only for obtaining satisfactory map- ping quality, but photogrammetric missions must be carried out in compliance with state regulations.Note de contenu : 1- Introduction
2- UAV Photogrammetry
3- Mission Planning and Flight Management
4- Measurements, Models and Estimation Methods
5- Developed MAV Platforms and Sensor Equipment
6- System and Sensor Calibration
7- Evaluation and Performance Assessment
8- Conclusion and PerspectivesNuméro de notice : 17459 Affiliation des auteurs : non IGN Autre URL associée : URL EPFL Thématique : IMAGERIE Nature : Thèse étrangère Note de thèse : thèse : Sciences : EPFL : 2017 DOI : 10.5075/epfl-thesis-7530 En ligne : https://www.sgc.ethz.ch/sgc-volumes/sgk-98.pdf Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=89684 Réservation
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Code-barres Cote Support Localisation Section Disponibilité 17459-01 35.10 Livre Centre de documentation Télédétection Disponible
Titre : ITRF local tie survey at Saint-John’s, Canada Type de document : Rapport Auteurs : Thomas Donal, Auteur ; Jean-Claude Poyard, Auteur Mention d'édition : version 1 Editeur : Saint-Mandé : Institut national de l'information géographique et forestière - IGN (2012-) Année de publication : 2017 Collection : Publications techniques en géodésie Sous-collection : Rapports techniques num. 28599 Importance : 52 p. Format : 21 x 30 cm Langues : Français (fre) Descripteur : [Vedettes matières IGN] Systèmes de référence et réseaux
[Termes IGN] Canada
[Termes IGN] co-positionnement
[Termes IGN] International Terrestrial Reference Frame
[Termes IGN] marégraphe
[Termes IGN] point de liaison (géodésie)
[Termes IGN] positionnement par DORIS
[Termes IGN] positionnement par GNSS
[Termes IGN] positionnement par ITGBRésumé : (auteur) The ITRF2014 realization (most recent frame of the International Terrestrial Reference System) computed by the ITRS product Centre (Geodesy Research Laboratory at IGN) is the result of the reference frames combination from four space geodesy techniques (i.e. GNSS, DORIS, SLR et VLBI). One way to achieve one common frame consists in adding to the combination results from co-located sites local tie surveys. The magnetic observatory in St. John’s (Canada) is equipped with a DORIS station, several permanent GNSS stations and geodetic marks tied with the former mobile VLBI station. Finally, a tide gauge set a few kilometres apart has been tied. This report describes the local tie survey carried out on July 2013 in St. John’s and the associated results. Note de contenu : 1- Introduction
2- Co-location site description
3- Local tie survey description
4- Computation and data analysis
5- Results
6- AppendicesNuméro de notice : 17563 Affiliation des auteurs : IGN (2012-2019) Thématique : POSITIONNEMENT Nature : Rapport de mission nature-HAL : Rapport DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91688 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 17563-01 7D Livre SGM K001 Exclu du prêt Documents numériques
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ITRF local tie survey at Saint-John’s, Canada - pdf auteurAdobe Acrobat PDF Lexique GNSS pour le positionnement [Commission GEOPOS, groupe de travail GNSS] / Françoise Duquenne (2017)
Titre : Lexique GNSS pour le positionnement [Commission GEOPOS, groupe de travail GNSS] Type de document : Dictionnaire / Usuel Auteurs : Françoise Duquenne , Éditeur scientifique ; Jacques Beilin , Auteur ; Florian Birot, Auteur ; Bernard Bonhoure, Auteur ; Philippe Bonnifait, Auteur ; Paul Chambon, Auteur ; Jonathan Chenal , Auteur ; Denis Laurichesse, Auteur ; Elise-Rachel Mathis , Auteur ; Laurent Morel, Auteur ; Norbert Suard, Auteur ; Joël Van Cranenbroeck, Auteur Editeur : Paris : Association Française de Topographie AFT Année de publication : 2017 Importance : 29 p. Format : 21 x 30 cm Langues : Français (fre) Descripteur : [Vedettes matières IGN] Terminologie
[Termes IGN] positionnement par GNSSIndex. décimale : 86.11 Dictionnaires techniques spécialisés en astronomie et géodésie Résumé : (Editeur) Ce lexique est élaboré dans le cadre du groupe de travail GNSS de la commision GOPOS du CNIG. L'objectif est de concevoir un lexique couvrant le domaine du positionnement par GNSS, en langue française. Il devrait permettre de se repérer dans le jargon des GNSS et non d'acquérir une connaissance approfondie des GNSS. Pour cela le groupe de travail conseille au lecteur de se référer entre autres à navipedia.net mis en ligne par l'ESA. Numéro de notice : 22924 Affiliation des auteurs : ENSG+Ext (2012-2019) Thématique : POSITIONNEMENT Nature : Dictionnaire nature-HAL : OuvrScient DOI : sans Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90850 Réservation
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