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The influence of artificial illumination of invar levelling rods / Štefan Rákay in Geodetski vestnik, vol 62 n° 4 (December 2018 - February 2019)  

Public [article]  inGeodetski vestnik > vol 62 n° 4 (December 2018 - February 2019) . - pp 619 - 629 Titre : The influence of artificial illumination of invar levelling rods Type de document : Article/Communication Auteurs : Štefan Rákay, Auteur ; Slavomír Labant, Auteur ; Karol Bartoš, Auteur ; Katarína Pukanská, Auteur Année de publication : 2018 Article en page(s) : pp 619 - 629 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Nivellement [Termes IGN] angle d'incidence [Termes IGN] détecteur à transfert de charge [Termes IGN] détection d'erreur [Termes IGN] éclairement lumineux [Termes IGN] erreur en altitude [Termes IGN] erreur systématique [Termes IGN] mire de nivellement [Termes IGN] niveau numérique [Termes IGN] stadia Invar Résumé : (auteur) Since the digital levels operate on the principle of image processing of the bar code of levelling rod, recorded by a CCD sensor, the proper lighting (i.e. illumination of the bar code) is important to achieve accurate results. The prevention of inappropriate lighting conditions is important for the correct recording of the image of bar code section. This paper examines the systematic error as a function of the angle of incidence at which an bar code is illuminated by artificial lighting in low light conditions. Further, the procedure of measurements and the analysis of results for the identification of such errors is proposed. The results of experimental measurements highlight the inappropriateness of bar code illumination at an angle of incidence of more than about 45 °. From the practical measurements, it was found that the angle of incidence 55 ° corresponds to an error of about 0.02 mm, which is twice as much as the resolution of the height measurement determined by the manufacturer. Numéro de notice : A2019-015 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.15292/geodetski-vestnik.2018.04.619-629 Date de publication en ligne : 30/11/2018 En ligne : https://doi.org/10.15292/geodetski-vestnik.2018.04.619-629 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=91624 [article]

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Experiences with the QDaedalus system for astrogeodetic determination of deflections of the vertical / Markus Hauk in Survey review, vol 49 n° 355 (October 2017)  

Public [article]  inSurvey review > vol 49 n° 355 (October 2017) . - pp 294 - 301 Titre : Experiences with the QDaedalus system for astrogeodetic determination of deflections of the vertical Type de document : Article/Communication Auteurs : Markus Hauk, Auteur ; C. Hirt, Auteur ; C. Ackermann, Auteur Année de publication : 2017 Article en page(s) : pp 294 - 301 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Géodésie physique [Termes IGN] astronomie de position [Termes IGN] Bavière (Allemagne) [Termes IGN] chambre zénithale [Termes IGN] champ de pesanteur local [Termes IGN] détecteur à transfert de charge [Termes IGN] déviation de la verticale [Termes IGN] tachéomètre Résumé : (Auteur) This paper explores the astrogeodetic deflection of the vertical (VD) determination with a light-weight tachymeter-based measurement system called ‘QDaedalus’ developed at ETH Zurich. A description of the relevant components of the system is given to show the set-up and operation. The measuring process including CCD-tachymeter calibration and the astronomical data processing are summarised. The paper then analyses the achievable accuracy of VDs based on new measurement data acquired in Bavaria over several nights. Our measurements were executed atop a pillar on the roof of the TUM and at six stations in the Bavarian Alps (Estergebirge) with highly accurate VDs from previous digital zenith camera measurements available. Our comparisons indicate an accuracy level of 0.15–0.20 arc-seconds for VDs measured with QDaedalus. As a conclusion, our results show that the QDaedalus system is a promising sensor for accurate local astronomical gravity field surveys when a zenith camera is not available. Numéro de notice : A2017-552 Affiliation des auteurs : non IGN Thématique : POSITIONNEMENT Nature : Article DOI : 10.1080/00396265.2016.1171960 En ligne : https://doi.org/10.1080/00396265.2016.1171960 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=86613 [article]

Atmospheric water vapour sensing by means of differential absorption spectrometry using solar and lunar radiation / Stefan Walter Münch (2014)  

Public Titre : Atmospheric water vapour sensing by means of differential absorption spectrometry using solar and lunar radiation Type de document : Thèse/HDR Auteurs : Stefan Walter Münch, Auteur Editeur : Zurich : Schweizerischen Geodatischen Kommission / Commission Géodésique Suisse Année de publication : 2014 Collection : Geodätisch-Geophysikalische Arbeiten in der Schweiz, ISSN 0257-1722 num. 92 Importance : 210 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-908440-35-2 Note générale : bibliographie, thèse publiée Diss., Eidgenössische Technische Hochschule ETH Zürich, Nr. 21491, 2013 Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Atmosphère [Termes IGN] correction troposphérique [Termes IGN] détecteur à transfert de charge [Termes IGN] pouvoir de résolution spectrale [Termes IGN] rayonnement solaire [Termes IGN] spectromètre [Termes IGN] spectrométrie [Termes IGN] teneur en vapeur d'eau [Termes IGN] troposphère Index. décimale : 47.50 Atmosphère Résumé : (auteur) Tropospheric water vapour plays a crucial role in the understanding of a variety of different atmospheric processes, ranging from local weather phenomena to global climate change. Regarding satellite geodesy, water vapour acts as disturbing factor for various measurement methods, causing path delays of radio signals and consequently leads to considerable biases in the measurement results. The spatial and temporal concentration distribution can hardly be modelled and therefore has to be determined instrumentally to correct the influence computationally. The application of the principle of “Differential Optical Absorption Spectroscopy” (DOAS) using the sun as radiation source to locally determine integrated water vapour concentrations (PW), has proven itself as a very potent methodology, with good relative and absolute accuracy, high temporal resolution and comparably low calibration efforts. It also seems especially well suited for validation purposes for independent measurement methods. The intention of the presented project is to implement the findings from the development of earlier prototype instruments and to contemplate several further aspects related with the DOAS approach to determine atmospheric water vapour: Improved temporal coverage of the measurement method through inclusion of night time measurements with the help of moonlight, which are enabled by means of a massively increased system sensitivity to deal with the up to six orders of magnitude lower intensity of the background radiation with respect to solar measurements. Further it is to investigate, how reliable acquisitions of sun transmission spectra can be achieved, when deploying the system on moving platforms, for possible future validation measurements of satellite-borne radiometer data on satellite ground tracks on the open sea. The prototype instruments developed should particularly feature high field versatility, requiring eased transportability, resistance to weather and not least the possibility of a fully automatic measurement procedure, including instrument self-calibration. For this purpose two identically constructed compact measurement systems were built. The instruments dispose of a custom-built telescope (heliostat principle) and an optically directly coupled spectrometer unit. The whole system is enclosed in a rugged aluminium hull, including most of the steering electronics. The motorized telescope is able to follow the moving light source fully autonomously, also with the platform moderately moving. A quasi-monochromator with an echelle grating as main dispersion element is used as spectrometer unit, allowing a compact architecture, a great spectral resolution and efficiency at the same time. Together with a back-thinned CCD detector highly resolved images of water vapour absorption lines can be obtained. The primary wavelength range lies between 789 nm and 802 nm, the reciprocal linear dispersion amounts to 7.3 pm/px at a focal length of just 400 mm. A motorized deflection mirror in the spectrometer allows the observation of adjacent spectral windows and serves for the highly precise position stabilization of the spectrum on the CCD sensor. Test measurements with the sun and the moon as background radiation source show the extraordinarily high system light throughput and the high spectral resolving power of the apparatus. However illumination dependent interference structures on the detector (etaloning) prevent the deduction of usable transmission spectra from the measured raw data. For that reason a variety of optical measures to homogenize the radiation entering the spectrometer with respect to field and aperture are examined. As a feasible solution, with sufficient radiation distribution and a still acceptable intensity attenuation, a short quartz light guiding fibre with a hexagonal cross section has been found and implemented. For instrumental control a software package has been developed, which autonomously handles the measurement process including the various calibration processes and the interaction of the various sensors and actuators. Additionally a variety of algorithms have been provided, helping to eliminate various defective influences in the raw data, as the correction of stray and false light portions or the elimination of interspersed beat structures in lunar spectra. Furthermore procedures which serve in spectrum processing have been supplied, as for the computation of a holistic intensity baseline or the dynamic determination of apparatus profiles. For the determination of the water vapour concentrations from the measured spectroscopic data established computational procedures could be used mostly. Various available spectroscopic databases have been analysed regarding the suitability of the listed absorption line parameters for the deduction of reliable water vapour concentrations. Comparison between the two identically built solar spectrometers yield considerable deviations of up to 1.5 kg/m 2 in the zenith integral concentrations which are presumably ascribable to systematic influences likely caused by unrecognized stray light influence. The mean value of the stochastic deviations amounts to about 1.1 % of the slant PW concentration. The cross-comparison with an independent measurement method, in this case GPS meteorology, however also shows significant divergences and thus point to the various further systematic effects which have to be examined more closely, as e.g. the uncertainty of the published spectroscopic parameters regarding line strength and line broadening as well as the baseline determination in the measured spectra. Despite the considerable sensitivity losses with respect to the originally planned design due to beam homogenization, the methodology has been successfully applied to lunar measurements, albeit with reduced accuracy as stated in stochastic appraisals and with considerably lower temporal resolution. The project presented here confirms and clarifies the possibilities of the application of DOAS for ground- based remote sensing of integral water vapour concentrations, but also gives clear indication on the different systematic biases which have to be examined more closely, e.g. regarding the accuracy of the spectroscopic parameters (both, for line strength and line broadening), as well as the determination procedure of the baseline in the measured spectra. This work also points out the chances as well as the serious difficulties which arise from the design, construction and deployment of highly integrated DOAS spectrometers of high performance. Regarding the application of various optical components and detectors for the development of similar instruments valuable insights have been gathered. Numéro de notice : 14913 Affiliation des auteurs : non IGN Autre URL associée : URL ETH Zurich Thématique : POSITIONNEMENT Nature : Thèse étrangère Note de thèse : PhD : Sciences : ETH Zurich : 2013 DOI : 10.3929/ethz-a-010006561 En ligne : http://e-collection.library.ethz.ch/view/eth:7591 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76813

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Sensor modelling and validation for linear array aerial and satellite imagery / Sultan Aksakal Kocaman (2009)  

Public Titre : Sensor modelling and validation for linear array aerial and satellite imagery Type de document : Thèse/HDR Auteurs : Sultan Aksakal Kocaman, Auteur ; Armin W. Gruen, Directeur de thèse ; Christian Heipke, Directeur de thèse Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 2009 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 106 Importance : 166 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906467-88-7 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] ADS40 [Termes IGN] capteur aérien [Termes IGN] capteur en peigne [Termes IGN] capteur linéaire [Termes IGN] capteur optique [Termes IGN] capteur spatial [Termes IGN] compensation par faisceaux [Termes IGN] détecteur à transfert de charge [Termes IGN] étalonnage de capteur (imagerie) [Termes IGN] image ALOS-PRISM [Termes IGN] modèle géométrique de prise de vue [Termes IGN] modélisation géométrique de prise de vue [Termes IGN] orientation du capteur [Termes IGN] Panchromatic Remote Sensing Instrument for Stereo Mapping [Termes IGN] pouvoir de résolution géométrique Index. décimale : 35.13 Prises de vues par capteurs spatiaux Résumé : (Auteur) The Linear Array CCD technology is widely used in the new generation aerial photogrammetric sensors and also in the high-resolution satellite optical sensors. In comparison to the Matrix (frame/area) Array sensors, the Linear Array CCD sensors have smaller number of detectors to cover the same swath width. In addition, the flexibility is higher in the physical sensor design. The conventional film cameras used in aerial photogrammetry are manufactured in frame format. The first remote sensing sensors for Earth observation employed film cameras as well. The recent sensor technologies of the optical remote sensing satellites are replaced with the Linear Array CCDs. In case of the aerial photogrammetric sensors, medium and small format aerial cameras are produced only in the frame format. The development in large format cameras is twofold. The Linear Array CCD and Matrix Array CCD sensors have been present in the industry since the year 2000. Due to the geometric differences between the Linear Array cameras and the frame cameras, the conventional photogrammetric procedures for the geometric processing of the Linear Array CCD images should be redefined or newly developed. The trajectory modeling is one of the main concepts, which entered into the field of photogrammetry with the aerial and satellite pushbroom sensors. The modified collinearity equations are extended with mathematical functions to model the image trajectory in the bundle adjustment. This study encompasses the triangulation of Linear Array CCD images with the use of different trajectory models. The self-calibration models are partially adapted from the frame sensors in accordance with the physical structures of the Linear Array CCD sensors. In general, the triangulation and self-calibration of the aerial and the satellite Linear Array CCD images show similarities in terms of trajectory modeling and the physical definitions of the additional parameters. The main difference is in the number unknown parameters defined in the bundle adjustment, which is calculated as a function of the number of lenses, the trajectory model configuration, and the number of Linear Array CCDs used in the sensor. Therefore, similar sensor modeling and calibration approaches are applied in this study, with necessary adjustments for each system. In order to obtain high accuracy point positioning, high quality image trajectory measurement is crucial. The given trajectory can be modeled in the adjustment by using constant and linear correction parameters, as well as higher order polynomials. This study investigates the three different trajectory models with three different mathematical approaches. Two of the models are investigated at different levels of sophistication by altering the model parameters. Two different aerial Linear Array CCD sensors, the STARIMAGER of former Starlabo Corporation, Japan, and the ADS40 sensor of the Leica Geosystems, Heerbrugg, are used for the practical investigations. The PRISM (Panchromatic Remote-sensing Instrument for Stereo Mapping) onboard of Japanese ALOS satellite launched by JAXA (Japan Aerospace Exploration Agency) in 2006 is the satellite Linear Array CCD sensor used for the application parts of this study. The two aerial Linear Array CCD sensors work with the TLS (Three-Line-Scanner) principle. Three or more Linear Array CCDs are located in the focal plane of a single lens with different viewing angles providing stereo capability. The PRISM sensor differs in the optical design with three camera heads, each associated with a different viewing angle. Due to the design differences between the sensors, two sets of additional 'parameters for self-calibration are applied in this study. The aerial TLS sensors share the same set of additional parameters due to similar interior geometries of the sensors. The self-calibration of the PRISM sensor uses a different set due to multiple lenses and also multiple CCD chips used to form each image line. The sensor orientation and calibration methods presented in this study are validated using a number of application datasets. The image datasets of the three sensors are acquired over specially established testfields. Triangulation results prove the importance of high quality trajectory measurements for accurate sensor orientation. When the given image trajectory has a low quality, a sophisticated trajectory model should be used together with a high number of ground control points. This study also shows that, despite their weaker sensor geometry, the Linear Array CCD sensors have reached the accuracy potential of the conventional frame imagery for point determination. In addition, similar to the conventional film sensors, self-calibration has proven as a powerful tool for modeling the systematic errors of the Linear Array CCD imagery, albeit the method should be applied with a great care. Note de contenu : 1 Introduction 1.1 Research Objectives 1.2 Review of Digital Optical Sensors 1.2.1 Point-based Sensors 1.2.2 Linear Array CCD Sensors 1.2.3 Frame Array CCD Sensors 1.3 Review of Sensor Calibration Approaches for Linear Array CCD Sensors 1.4 Review of Sensor Orientation Methods for Linear Array CCD Sensors 1.4.1 Direct vs. Indirect Georeferencing 1.4.2 Rigorous vs. Generic Models for Georeferencing 1.5 Quality Analysis and Validation for the Geometric Processing Methods 1.6 Outline 2 Characterizations of the Linear Array CCD Sensor Geometries 2.1 Optical System Specification 2.2 Line Geometry 2.3 Resolution Specification 2.3.1 Spatial Resolution 2.3.2 Radiometric Resolution 2.3.3 Spectral Resolution 2.3.4 Temporal Resolutions of Satellite Sensors 2.4 Operation Principles 2.4.1 Sensor and Platform Synchronization 2.4.2 Stereo Acquisition 2.4.3 Platform Stabilization 3 Calibration Parameters for the Linear Array CCD Sensors . 3.1 Optical System Related Parameters 3.1.1 Principal Point Displacement 3.1.2 Camera Constant 3.1.3 Lens Distortions 3.2 CCD Line Related Parameters 3.2.1 Scale effect 3.2.2 Rotation 3.2.3 Displacement from the Principal Point 3.2.4 Bending 4 Methodology for Sensor Orientation and Calibration 4.1 Preparation for Rigorous Sensor Orientation 4.1.1 Image Trajectory Extraction 4.1.2 Interior Orientation Extraction 4.1.3 Coordinate System Transformations 4.2 Rigorous Sensor Orientation 4.2.1 Modified Bundle Adjustment with Trajectory Modeling 4.2.2 Self-calibration Method 4.2.3 Weighting Scheme of the Bundle Adjustment 4.2.4 Accuracy Assessment of the Bundle Adjustment 4.2.5 Processing time 5 Applications 5.1 Starlmager Sensor 5.1.1 Applications over the Yoriichio Testfield, Japan 5.1.2 Findings and Discussion 5.2 ADS40 Sensor 5.2.1 Applications to Testfields 5.2.2 Findings and Discussion 5.3 The ALOS/PRISM Sensor 5.3.1 Introduction 5.3.2 Applications to Testfields 5.3.3 Findings and Discussion 6 Conclusions and Outlook 6.1 Summary 6.2 Conclusions 6.3 Recommendations for Future Work Numéro de notice : 15509 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère En ligne : http://dx.doi.org/10.3929/ethz-a-005780510 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=62742

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Orientation and self-calibration of ALOS PRISM imagery / S. Kocaman in Photogrammetric record, vol 23 n° 123 (September - November 2008)  

Public [article]  inPhotogrammetric record > vol 23 n° 123 (September - November 2008) . - pp 323 - 340 Titre : Orientation and self-calibration of ALOS PRISM imagery Type de document : Article/Communication Auteurs : S. Kocaman, Auteur ; Armin W. Gruen, Auteur Année de publication : 2008 Conférence : ISPRS 2007, High-Resolution Earth Imaging for Geospatial Information workshop 29/05/2007 01/06/2007 Hanovre Allemagne Article en page(s) : pp 323 - 340 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie spatiale [Termes IGN] auto-étalonnage [Termes IGN] capteur en peigne [Termes IGN] compensation par faisceaux [Termes IGN] détecteur à transfert de charge [Termes IGN] élément d'orientation interne [Termes IGN] erreur systématique [Termes IGN] géoréférencement [Termes IGN] image à très haute résolution [Termes IGN] image ALOS-PRISM [Termes IGN] modélisation géométrique de prise de vue [Termes IGN] orientation d'image [Termes IGN] pas d'échantillonnage au sol Résumé : (Auteur) High-resolution satellite images (HRSI) at sub-5 m footprint are becoming increasingly available. A set of algorithms for processing of HRSI has been developed at the Institute of Geodesy and Photogrammetry (IGP), ETH Zurich and realised in a software suite called Satellite Image Precision Processing (SAT-PP). The software has been used for the processing of a number of high resolution satellite sensors, such as IKONOS, QuickBird, SPOT 5 HRS/HRG, Cartosat-1 and ALOS PRISM. PRISM is a panchromatic radiometer carried on board the Japanese ALOS satellite. It has three optical systems for forward, nadir and backward view with 2·5 m ground sample distance (GSD). The photogrammetric processing of PRISM imagery has special requirements owing to the linear array CCD sensor structure and special characteristics of the interior geometry and exterior orientation. As a member of the ALOS calibration/validation team, new algorithms for geometric processing of the PRISM images have been implemented at the IGP, in particular for the interior orientation and self-calibration. The physical sensor model in SAT-PP is refined according to the multiple camera heads of the sensor. The rigorous model for PRISM is based on a modified bundle adjustment with the possibility of using two different trajectory models. The self-calibration is introduced into the adjustment to model the systematic errors of the sensor and the system as a whole. The methods of georeferencing and digital surface model (DSM) generation were tested using the PRISM data-sets acquired over five different testfields. The rigorous sensor model performed well and resulted in sub-pixel accuracy for point positioning in all testfields. The self-calibration model has been tested in two different phases of the project separately. In the initial phase, where interior orientation data was not available, the use of the self-calibration was essential to achieve good accuracy. However, in the later phase the relative positions of the CCD chip detectors on the focal plane were provided by the Japan Aerospace Exploration Agency (JAXA) and the improvements by self-calibration became less significant. A detailed analysis of the DSM generation is presented in another publication. Copyright RS&PS + Blackwell Publishing Numéro de notice : A2008-396 Affiliation des auteurs : non IGN Thématique : IMAGERIE/POSITIONNEMENT Nature : Article DOI : 10.1111/j.1477-9730.2008.00493.x En ligne : https://doi.org/10.1111/j.1477-9730.2008.00493.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=76551 [article]

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106-08031	RAB	Revue	Centre de documentation	En réserve L003	Disponible

Eléments de physique pour l'imagerie aérienne et spatiale et la géodésie [diaporama pour le master PPMD] / Michel Kasser (2008) 

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Determination and improvement of spatial resolution of the CCD-line-scanner system ADS40 / R. Reulke in ISPRS Journal of photogrammetry and remote sensing, vol 60 n° 2 (April 2006)  

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Gigapixel frame images: is the holy grail of airborne digital frame imaging in sight? (Part 2) / Gordon Petrie in Geoinformatics, vol 9 n° 2 (01/03/2006)

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Etude bibliographique pour la mise en place d'une chaine d'acquisition multicapteurs très haute résolution sur un vecteur volant à basse altitude / Antoine Gademer (2006)

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Airborne pushbroom line scanners: an alternative to digital frame cameras / Gordon Petrie in Geoinformatics, vol 8 n° 1 (01/02/2005)

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Salle des Fêtes de Francfort : un pari logistique et technique / K. Jödicke in Géomètre, vol 2003 n° 10 (octobre 2003)

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Coup d'œil d'ensemble sur les nouvelles méthodes de levé topographique / Claude Million in Géotop, n° 170 (septembre 2003) 

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Capteurs d'images CCD et CMOS : comparaison des technologies et perspectives / P. Magnan in Géomatique expert, n° 24 (01/04/2003)

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Design and application of high-resolution imaging systems / R. Reulke in GIS Geo-Informations-Systeme, vol 2003 n° 3 (März 2003)

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Zur Automation berührungsloser 3D-Objekterfassung im Nahbereich / M. Hovenbitzer (2003)

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