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DMC geometry analysis and virtual image characterisation / R. Alamus in Photogrammetric record, vol 23 n° 124 (December 2008 - February 2009)  

Public [article]  inPhotogrammetric record > vol 23 n° 124 (December 2008 - February 2009) . - pp 353 - 371 Titre : DMC geometry analysis and virtual image characterisation Type de document : Article/Communication Auteurs : R. Alamus, Auteur ; W. Kornus, 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 353 - 371 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] aérotriangulation automatisée [Termes IGN] auto-étalonnage [Termes IGN] chambre à grand format [Termes IGN] compensation par faisceaux [Termes IGN] DMC [Termes IGN] erreur systématique [Termes IGN] espace image [Termes IGN] géométrie de l'image [Termes IGN] géoréférencement [Termes IGN] modélisation géométrique de prise de vue [Termes IGN] points homologues [Termes IGN] précision géométrique (imagerie) [Termes IGN] rapport base hauteur [Termes IGN] résidu Résumé : (Auteur) Since the advent of the first large format digital aerial cameras, high expectations have been placed on their performance. The dream of obtaining aerial images virtually free of geometric errors and with greater radiometric quality is getting close. Nevertheless, systematic image residuals, unexpected height errors in aerial triangulation and the need for additional self-calibration parameters have been reported since 2005. In this paper a preliminary analysis of the theoretical accuracies in aerial triangulation using the Zeiss/Intergraph (Z/I) Digital Mapping Camera (DMC) and an analogue camera is conducted, motivated by those recent reports. This analysis considers a mathematical model where the image has conical geometry and is free of systematic errors. The influence on the propagated block accuracy of the base-to-height ratio, image pointing precision (both manual and automatic), GPS observations for projection centres and of pass/tie point density is studied. Moreover, the expected accuracy in the aerial triangulation of analogue images using current procedures (having regard to the a priori accuracy for image pointing, ground control measurement and GPS and pass/tie point density) is computed. The goal of this theoretical study is to find the requirements for aerial triangulation with DMC data which would yield the same or an even higher level of accuracy than that obtained with analogue data under the same conditions. The paper continues with a check on the conclusions of this theoretical analysis, using real data-sets and aerial triangulation set-up, which fit with the theoretical analysis. The results prove that the expected theoretical accuracy in aerial triangulation is only obtained if an appropriate self-calibration parameter set is considered in the bundle block adjustment and/or if good GPS observations are available. These requirements result from the unfavourable propagation from unmodelled systematic error in the DMC image blocks. Some authors have detected systematic residuals in the order of one-tenth of a pixel rms in DMC image space. For this reason, investigations are being carried out on systematic error characterisation, distribution in image space and stability over time and flying height, and systematic error modelling, using self-calibration parameter sets and applying correction grids. Finally, conclusions are drawn from the investigations. Copyright RS&PS + Blackwell Publishing Numéro de notice : A2008-417 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2008.00504.x En ligne : https://doi.org/10.1111/j.1477-9730.2008.00504.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=29488 [article]

Studies on DMC geometry / R. Alamus in ISPRS Journal of photogrammetry and remote sensing, vol 60 n° 6 (September 2006)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 60 n° 6 (September 2006) . - pp 375 - 386 Titre : Studies on DMC geometry Type de document : Article/Communication Auteurs : R. Alamus, Auteur ; W. Kornus, Auteur ; J. Talaya, Auteur Année de publication : 2006 Article en page(s) : pp 375 - 386 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] analyse comparative [Termes IGN] chambre DTC [Termes IGN] DMC [Termes IGN] données lidar [Termes IGN] étalonnage de capteur (imagerie) [Termes IGN] modèle numérique de surface [Termes IGN] photogrammétrie aérienne [Termes IGN] précision géométrique (imagerie) Résumé : (Auteur) Since the ISPRS Congress 2000 in Amsterdam, there are great expectations in matrix-CCD based digital cameras for aerial photogrammetry and mapping applications. During the last two years the number of DMC cameras in the market has raised significantly (32 cameras were sold until March 2006). This paper discusses the DMC accuracy focusing on the role of self-calibration parameters and the assessment of automatic DEM quality. This investigation concluded that under the current status of DMC an appropriate set of self-calibration parameters is necessary in order to achieve theoretical accuracy and precision, which were discussed in early literature. In the following discussions, the accuracy of the DMC is analyzed comparing its performance in automatic DEM generation to that of an analog camera using a Lidar DEM as reference. Despite the fact that the higher image quality of the DMC should overcome the poorer base-to-height ratio, the presented results did not reach the expected accuracies. However, our current study is not yet conclusive on this topic because the DMC, the analog images and the LIDAR data have not been acquired at the same time. Numéro de notice : A2006-410 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2006.05.006 En ligne : https://doi.org/10.1016/j.isprsjprs.2006.05.006 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28134 [article]

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DEM generation from SPOT-5 3-fold along track stereoscopic imagery using autocalibration / W. Kornus in ISPRS Journal of photogrammetry and remote sensing, vol 60 n° 3 (May 2006)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 60 n° 3 (May 2006) . - pp 147 - 159 Titre : DEM generation from SPOT-5 3-fold along track stereoscopic imagery using autocalibration Type de document : Article/Communication Auteurs : W. Kornus, Auteur ; R. Alamus, Auteur ; et al., Auteur Année de publication : 2006 Article en page(s) : pp 147 - 159 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie spatiale [Termes IGN] auto-étalonnage [Termes IGN] compensation par faisceaux [Termes IGN] erreur moyenne quadratique [Termes IGN] espace objet [Termes IGN] image SPOT-HRS [Termes IGN] modèle numérique de surface [Termes IGN] modèle numérique de terrain [Termes IGN] point d'appui [Termes IGN] précision du positionnement [Termes IGN] semis de points Résumé : (Auteur) This paper describes the derivation and accuracy assessment of Digital Elevation Models (DEM) from 3-fold along-track stereoscopic SPOT-5 imagery. The work was conducted in the scope of the HRS (Haute Resolution Stereoscopique)-Scientifïc Assessment Program, organized by the Centre National d'Etudes Spatiales (CNES) and the International Society of Photogrammetry and Remote Sensing (ISPRS). The orientation of the SPOT-5 image scene is reconstructed by bundle adjustment using ground control points. The functional model is based on correction polynomials and permits autocalibration. At 17 independent check points a RMS-error of 2 m was achieved. DEM are produced in two different ways: The more rigorous way employs an automatic region growing image matching process generating a dense point cloud in image space, transforms it into the object space using the estimated model parameters and converts it into a regular grid DEM. In a second approach the commercial software ISAE and rational functions are applied. The comparison with a digital terrain model (DTM) of superior accuracy yields standard deviations better than 5 m in flat and moderate terrain and better than 10 m in mountainous regions. With ISAE a DEM for the entire image area (approx. 60 x 80 km) is produced with a standard deviation of approximately 8 m. All grid points were generated fully automatically, i.e. the presented standard deviations still include the effect of large differences between the produced DEM and the DTM. Copyright ISPRS Numéro de notice : A2006-226 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2005.12.004 En ligne : https://doi.org/10.1016/j.isprsjprs.2005.12.004 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=27953 [article]

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