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Termes IGN > sciences naturelles > physique > traitement d'image > filtrage numérique d'image > filtre de Wallis
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Improving local adaptive filtering method employed in radiometric correction of analogue airborne campaigns / Lâmân Lelégard (2022)
Titre : Improving local adaptive filtering method employed in radiometric correction of analogue airborne campaigns Type de document : Article/Communication Auteurs : Lâmân Lelégard Editeur : International Society for Photogrammetry and Remote Sensing ISPRS Année de publication : 2022 Collection : International Archives of Photogrammetry, Remote Sensing and Spatial Information Sciences, ISSN 1682-1750 num. 43-B3 Projets : HIATUS / Giordano, Sébastien Conférence : ISPRS 2022, Commission 3, 24th ISPRS Congress, Imaging today, foreseeing tomorrow 06/06/2022 11/06/2022 Nice France OA ISPRS Archives Importance : pp 1217 - 1222 Format : 21 x 30 cm Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse en composantes principales
[Termes IGN] contraste local
[Termes IGN] correction radiométrique
[Termes IGN] fenêtre (informatique)
[Termes IGN] filtre de Wallis
[Termes IGN] morphologie mathématiqueRésumé : (auteur) An orthophotomosaic is as a single image that can be layered on a map. It is produced from a set of aerial images impaired by radiometric inhomogeneity mostly due to atmospheric phenomena, like hotspot, haze or high altitude clouds shadows as well as the camera itself, like lens vignetting. These create some unsightly radiometric inhomogeneity in the mosaic that could be corrected by using a local adaptive filter, also named Wallis filter. Yet this solution leads to a significant loss of contrast at small scales. This current work introduces two elementary studies. In a first time, in order to quantify the loss of contrast due to the use of Wallis filter, a simple multi-scale score is proposed based on mathematical morphology operations. In a second time, an optimal window size for the filter is identified by considering some systematic radiometric behaviours in the images forming the mosaic through Principal Component Analysis (PCA). These two elementary studies are preliminary steps leading to a method of radiometric correction combining Wallis filtering and PCA. Numéro de notice : C2022-015 Affiliation des auteurs : UGE-LASTIG (2020- ) Thématique : IMAGERIE/INFORMATIQUE Nature : Communication nature-HAL : ComAvecCL&ActesPubliésIntl DOI : 10.5194/isprs-archives-XLIII-B3-2022-1217-2022 Date de publication en ligne : 31/05/2022 En ligne : https://doi.org/10.5194/isprs-archives-XLIII-B3-2022-1217-2022 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=100841
Titre : Novel fusion approach on automatic object extraction from spatial data: case study Worldview-2 and TOPO5000 Type de document : Article/Communication Auteurs : Umut Gunes Sefercik, Auteur ; Serkan Karakis, Auteur ; Can Atalay, Auteur ; Ibrahim Yigit, Auteur ; Umit Gokmen, Auteur Année de publication : 2018 Article en page(s) : pp 1139 - 1154 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] analyse d'image orientée objet
[Termes IGN] détection d'objet
[Termes IGN] détection du bâti
[Termes IGN] extraction automatique
[Termes IGN] extraction de traits caractéristiques
[Termes IGN] extraction du réseau routier
[Termes IGN] filtre de Wallis
[Termes IGN] image numérique
[Termes IGN] image Worldview
[Termes IGN] modèle numérique de surface
[Termes IGN] TurquieRésumé : (auteur) The automatic extraction of information content from remotely sensed data is always challenging. We suggest a novel fusion approach to improve the extraction of this information from mono-satellite images. A Worldview-2 (WV-2) pan-sharpened image and a 1/5000-scaled topographic vector map (TOPO5000) were used as the sample data. Firstly, the buildings and roads were manually extracted from WV-2 to point out the maximum extractable information content. Subsequently, object-based automatic extractions were performed. After achieving two-dimensional results, a normalized digital surface model (nDSM) was generated from the underlying digital aerial photos of TOPO5000, and the automatic extraction was repeated by fusion with the nDSM to include individual object heights as an additional band for classification. The contribution was tested by precision, completeness and overall quality. Novel fusion technique increased the success of automatic extraction by 7% for the number of buildings and by 23% for the length of roads. Numéro de notice : A2019-047 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1080/10106049.2017.1353646 Date de publication en ligne : 27/07/2017 En ligne : https://doi.org/10.1080/10106049.2017.1353646 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=92068
in Geocarto international > vol 33 n° 10 (October 2018) . - pp 1139 - 1154[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 059-2018041 RAB Revue Centre de documentation En réserve L003 Disponible
Titre : A fully automatic approach to register mobile mapping and airborne imagery to support the correction of plateform trajectories in GNSS-denied urban areas Type de document : Article/Communication Auteurs : Phillipp Jende, Auteur ; Francesco Nex, Auteur ; Markus Gerke, Auteur ; M. George Vosselman, Auteur Année de publication : 2018 Article en page(s) : pp 86 - 99 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique
[Termes IGN] appariement géométrique
[Termes IGN] extraction de traits caractéristiques
[Termes IGN] filtre de Wallis
[Termes IGN] GNSS assisté pour la navigation
[Termes IGN] image aérienne
[Termes IGN] image terrestre
[Termes IGN] orientation d'image
[Termes IGN] orthoimage
[Termes IGN] point d'appui
[Termes IGN] précision décimétrique
[Termes IGN] système de numérisation mobile
[Termes IGN] zone urbaineRésumé : (Auteur) Mobile Mapping (MM) solutions have become a significant extension to traditional data acquisition methods over the last years. Independently from the sensor carried by a platform, may it be laser scanners or cameras, high-resolution data postings are opposing a poor absolute localisation accuracy in urban areas due to GNSS occlusions and multipath effects. Potentially inaccurate position estimations are propagated by IMUs which are furthermore prone to drift effects. Thus, reliable and accurate absolute positioning on a par with MM's high-quality data remains an open issue. Multiple and diverse approaches have shown promising potential to mitigate GNSS errors in urban areas, but cannot achieve decimetre accuracy, require manual effort, or have limitations with respect to costs and avail-ability. This paper presents a fully automatic approach to support the correction of MM imaging data based on correspondences with airborne nadir images. These correspondences can be employed to correct the MM plat-form's orientation by an adjustment solution. Unlike MM as such, aerial images do not suffer from GNSS oc-clusions, and their accuracy is usually verified by employing well-established methods using ground control points. However, a registration between MM and aerial images is a non-standard matching scenario, and requires several strategies to yield reliable and accurate correspondences. Scale, perspective and content strongly vary between both image sources, thus traditional feature matching methods may fail. To this end, the registration process is designed to focus on common and clearly distinguishable elements, such as road markings, manholes, or kerbstones. With a registration accuracy of about 98%, reliable tie information between MM and aerial data can be derived. Even though, the adjustment strategy is not covered in its entirety in this paper, accuracy results after adjustment will be presented. It will be shown that a decimetre accuracy is well achievable in a real data test scenari Numéro de notice : A2018-285 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2018.04.017 Date de publication en ligne : 30/04/2018 En ligne : https://doi.org/10.1016/j.isprsjprs.2018.04.017 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=90397
in ISPRS Journal of photogrammetry and remote sensing > vol 141 (July 2018) . - pp 86 - 99[article]Exemplaires(3)
Code-barres Cote Support Localisation Section Disponibilité 081-2018071 RAB Revue Centre de documentation En réserve L003 Disponible 081-2018073 DEP-EXM Revue LASTIG Dépôt en unité Exclu du prêt 081-2018072 DEP-EAF Revue Nancy Dépôt en unité Exclu du prêt
Titre : Interest operators for feature-based matching in close range photogrammetry Type de document : Article/Communication Auteurs : I. Jazayeri, Auteur ; Clive Simpson Fraser, Auteur Année de publication : 2010 Article en page(s) : pp 24 - 41 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique
[Termes IGN] appariement de points
[Termes IGN] bloc d'images
[Termes IGN] filtre de Wallis
[Termes IGN] photogrammétrie métrologique
[Termes IGN] point d'intérêtRésumé : (Auteur) Although automated object surface reconstruction via feature-based matching is commonly employed in both stereoscopic close range and topographic photogrammetry, it has rarely been used in conjunction with multi-image, convergent photogrammetric networks. A prerequisite for feature-based matching of distinct points is the application of interest operators to provide the dense arrays of candidate feature points within the images forming the network. This paper describes an evaluation of three interest operators, the Förstner, SUSAN and FAST algorithms, the aim being to assess which is optimal for feature-based matching in convergent close range photogrammetry. Following a brief review of the development of interest operators, a description of the three operators is provided, with the recently developed FAST operator being discussed in more detail. The merits of image pre-processing via the Wallis filter are also outlined, after which the performance of the interest operators is experimentally assessed within an eight-image network on the basis of accuracy of interest-point localisation, detection rate and speed. The findings of the evaluation are that, of the Förstner, SUSAN and FAST operators, the FAST, which has not been employed to a significant extent in photogrammetry to date, is optimal for feature-based matching in multi-image close range networks. Copyright RS&PS + Blackwell Publishing Numéro de notice : A2010-061 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2009.00559.x En ligne : https://doi.org/10.1111/j.1477-9730.2009.00559.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=30257
in Photogrammetric record > vol 25 n° 129 (March - May 2010) . - pp 24 - 41[article]Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 106-2010011 RAB Revue Centre de documentation En réserve L003 Disponible
Titre : Automatic Digital Surface Model (DSM) generation from linear array images Type de document : Thèse/HDR Auteurs : Li Zhang, Auteur Editeur : Zurich : Institut für Geodäsie und Photogrammetrie IGP - ETH Année de publication : 2005 Collection : IGP Mitteilungen, ISSN 0252-9335 num. 88 Importance : 199 p. Format : 21 x 30 cm ISBN/ISSN/EAN : 978-3-906467-55-9 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image
[Termes IGN] appariement d'images
[Termes IGN] B-Spline
[Termes IGN] chambre DTC
[Termes IGN] filtre de Wallis
[Termes IGN] fonction de transfert de modulation
[Termes IGN] modèle numérique de surface
[Termes IGN] triangulation de DelaunayIndex. décimale : 35.20 Traitement d'image Résumé : (Auteur) This dissertation addresses the topic of automatic Digital Surface Model (DSM) generation from linear array images. Research on this issue is mainly motivated by the following facts: In recent years, CCD linear array sensors are widely used to acquire high-quality, high-resolution panchromatic and multispectral imagery for photogrammetric and remote sensing applications. Most of these sensors have the ability to acquire more than 2 views of the terrain surface during a single flight line or orbit. The processing of these kinds of images provides a challenge for algorithmic redesign and this opens the possibility to reconsider and improve many photogrammetric processing components. In particular, automatic DSM generation through image matching techniques is one of the main topics. Although this topic has gained much attention in the past years and a wide variety of approaches have been developed, the accuracy performance and the problems encountered are very similar in the major approaches and the performance of these approaches does by far not live up to the standards set by manual measurements. Therefore, efforts have to be made to develop a general framework for automatic DSM generation from linear array images, into which specific algorithms can be inserted easily, investigated and combined in order to achieve reasonable results in terms of precision and reliability.
In this dissertation, an image matching approach for automatic DSM generation from linear array images, which has the ability to provide dense, precise and reliable results is presented. The approach integrates different matching primitives, uses available and explicit knowledge concerning the image geometry and radiometry information, combines several image matching algorithms and automatic quality control, and works with a coarse-to-fine hierarchical matching strategy. The most outstanding characteristics are the efficient utilisation of multiple images and the integration of multiple matching primitives. With this approach, the linear array images and the given or previously triangulated orientation elements are taken as inputs. After pre-processing of the original images and production of the image pyramids, the matches of 3 kinds of features, i.e. feature points, grid points and edges, on the original resolution images are finally found progressively starting from the low density features on the images with the lowest resolution. An intermediate DSM is reconstructed from the matched features on each level of the pyramid by using the constrained Delauney triangulation method, which in turn is used in the subsequent pyramid level for the approximations and self-tuning of the matching parameters. Finally least squares matching methods are used to achieve more precise matches for al] the matched features and identify some false matches.
The presented approach essentially consists of several mutually connected components: the image pre-processing, the multiple primitive multi-image (MPM) matching, the refined matching and the system performance evaluation. Each of them is important and possesses particular features, which are fully elaborated in different parts of the dissertation.
First of all, a pre-processing method, which combines an adaptive smoothing filter and the Wallis filter, is used in order to reduce the effects of the inherent radiometric problems and optimize the images for subsequent feature extraction and image matching procedure. The method mainly consists of 3 processing stages. In the first stage, the noise characteristics of the images are analyzed quantitatively in both homogeneous and non-homogeneous image regions. The image blur problem (image unsharpness) is also addressed through the analysis of the image's Modulation Transfer Function (MTF). Then, an adaptive smoothing filter is applied to reduce the noise level and at the same time, to sharpen edges and preserve even fine detail such as corners and line end-points. Finally, the Wallis filter is applied to strongly enhance and sharpen the already existing texture patterns.
The MPM matching procedure is the core of our approach. In this approach, the matching is performed with the aid of multiple images, incorporating multiple matching primitives feature points, grid points and edges, integrating local and global image information and, utilizing a coarse-to-fine hierarchical matching strategy.
The MPM approach mainly consists of 3 integrated subsystems: point extraction and matching procedure, edge extraction and matching procedure and relational matching procedure. These 3 subsystems are followed through the image pyramid and the results at higher levels are used for guidance at the lower levels. At each pyramid level, the correspondence is established in two matching stages - locally and globally. In the local matching stage dense patterns of points and edges are matched. A unique and robust matching algorithm - The Geometrically Constrained Cross-Correlation (GC3 ) algorithm is employed to provide matching candidates for points and edge pixels. The algorithm. is based on the concept of multi-image matching guided from the object space and allows reconstruction of 3D objects by matching all the images at the same time, without having to go through the processing of all individual stereo-pairs and the merging of all stereo-pair results. The GC3 method, with the self-tuning of the parameters, leads to a reduction of problems caused by occlusions, multiple solutions and surface discontinuities. The global matching stage is responsible for imposing global consistency among the candidate matches in order to disambiguate the multiple candidates and avoid mismatches. The global matching is resolved by a probability relaxation based relational matching method. It uses the local support provided by points within a 2D neighbourhood. This corresponds to imposing a piecewise smoothness constraint, in which the matched edges serve as breaklines in order to prohibit the smoothness constraint crossing these edges and preserves the surface discontinuities.
The modified Multiphoto Geometrically Constrained Matching (MPGC) and the Least Squares B-Spline Snakes (LSB-Snakes) methods are used to achieve potentially sub-pixel accuracy matches and identify some inaccurate and possibly false matches. The DSM derived from the MPM module provides good enough approximations for these methods and increases the convergence rate. The initial values of the shaping parameters in MPGC matching can also be predetermined by using the image geometry and the derived DSM data. Finally, for each matched point, a reliability indicator is assigned based on the analysis of the matching results. For edges, a simplified version of the LSB-Snakes is implemented to match the edges, which are represented by parametric linear B-spline functions in object space. With this method, the parameters of linear B-spline functions of the edges in object space are directly estimated, together with the matching parameters in the image spaces of multiple images.
The system bas been tested extensively of linear array images with different image resolution and over different land cover types. The accuracy evaluation is based on the comparison between high quality DEMs/DSMs derived from airborne Laser Scanner or manual measurements and the automatically extracted DSMs. As evidenced by the visual inspection of the results, we can reproduce not only the general geomorphological features of the terrain relief, but also detailed features of relief. The results from the quantitative accuracy test indicate that the presented concept has the capability to give good and encouraging results. If the bias introduced by trees and buildings is taken out, we can expect a height accuracy of one pixel or even better from satellite imagery as "best case" scenario. In case of very high resolution TLS/SI images (footprint 8 cm and better) it is obvious that the "one pixel rule" cannot be maintained any more. Alone surface roughness and modeling errors will lead to larger deviations, such that an accuracy of 2 to 5 pixels should be considered an acceptable result.Numéro de notice : 13290 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Thèse étrangère DOI : 10.3929/ethz-a-005055636 En ligne : http://dx.doi.org/10.3929/ethz-a-005055636 Format de la ressource électronique : URL Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=54962 Exemplaires(1)
Code-barres Cote Support Localisation Section Disponibilité 13290-01 35.20 Livre Centre de documentation Télédétection Disponible Permalink
