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Improving traffic sign recognition results in urban areas by overcoming the impact of scale and rotation / R. Yazdan in ISPRS Journal of photogrammetry and remote sensing, vol 171 (January 2021)  

Public [article]  inISPRS Journal of photogrammetry and remote sensing > vol 171 (January 2021) . - pp 18 - 35 Titre : Improving traffic sign recognition results in urban areas by overcoming the impact of scale and rotation Type de document : Article/Communication Auteurs : R. Yazdan, Auteur ; M. Varshosaz, Auteur Année de publication : 2021 Article en page(s) : pp 18 - 35 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes descripteurs IGN] apprentissage profond [Termes descripteurs IGN] base de données d'images [Termes descripteurs IGN] classification par réseau neuronal convolutif [Termes descripteurs IGN] classification par séparateurs à vaste marge [Termes descripteurs IGN] corrélation à l'aide de traits caractéristiques [Termes descripteurs IGN] corrélation croisée normalisée [Termes descripteurs IGN] couple stéréoscopique [Termes descripteurs IGN] détection automatique [Termes descripteurs IGN] modèle stéréoscopique [Termes descripteurs IGN] reconnaissance d'objets [Termes descripteurs IGN] segmentation d'image [Termes descripteurs IGN] SIFT (algorithme) [Termes descripteurs IGN] signalisation routière [Termes descripteurs IGN] SURF (algorithme) [Termes descripteurs IGN] Téhéran [Termes descripteurs IGN] transformation de Hough [Termes descripteurs IGN] zone urbaine Résumé : (auteur) Automatic detection and recognition of traffic signs have many applications. However, some problems can affect the accuracy of the existing algorithms, such as changes in environmental light conditions, shadows, the presence of objects of the same colour, significant changes in scale and rotation, as well as obstacles in front of the traffic signs. To overcome these difficulties, a reference image database is usually used that includes different modes of appearing the traffic signs in the images. In order to overcome the effects of scale and rotation, in this paper a new method is presented in which only one reference image is needed for each sign to recognise the traffic sign in an image. In the proposed method, imaging is done in stereo. Using the captured image pair, a virtual image is generated which is then used to recognise the sign. As a result, the recognition is carried out with a minimum number of reference images. Experiments show that the proposed algorithm significantly improves recognition results. The traffic signs are recognised with 93.1% accuracy that enjoys a 4.9% improvement over traditional methods. Numéro de notice : A2021-010 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.1016/j.isprsjprs.2020.10.003 date de publication en ligne : 06/11/2020 En ligne : https://doi.org/10.1016/j.isprsjprs.2020.10.003 Format de la ressource électronique : url article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=96304 [article]

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Development of a new laser triangulation system based on an optical frame of reference / A. Abzal in Photogrammetric record, vol 26 n° 135 (September - November 2011)  

Public [article]  inPhotogrammetric record > vol 26 n° 135 (September - November 2011) . - pp 293 - 306 Titre : Development of a new laser triangulation system based on an optical frame of reference Type de document : Article/Communication Auteurs : A. Abzal, Auteur ; M. Varshosaz, Auteur ; M. Saadatseresht, Auteur Année de publication : 2011 Article en page(s) : pp 293 - 306 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes descripteurs IGN] balayage laser [Termes descripteurs IGN] chambre de prise de vue numérique [Termes descripteurs IGN] lasergrammétrie [Termes descripteurs IGN] photographie terrestre [Termes descripteurs IGN] précision géométrique (imagerie) [Termes descripteurs IGN] triangulation locale Résumé : (Auteur) In this paper a new triangulation-based laser scanner is presented which has a simple, yet strong, flexible and low-cost structure. A digital camera and three laser line projectors are the main components of the system. One of the laser projectors is positioned vertically, while the other two are horizontal. The former scans the object, whereas the latter two establish an optical frame which is used, in part, to define the plane containing the vertical laser projector at each step of scanning. At each step, an image is taken which includes the object along with the projected laser lines. By intersecting the vertical and horizontal lines a couple of points are formed which, along with the calibration information of the system, enable the extraction of the object coordinates. Results of the tests carried out show that by using an optical frame of this nature, the process of scanning is greatly facilitated. That is, the scanner can easily be used to scan objects of different size and dimensions. Within the current configuration, the system enables measurements with an accuracy of 1/1600. Also, as the system has a rigorous basis, its accuracy can be increased if improved hardware is provided. Numéro de notice : A2011-385 Affiliation des auteurs : non IGN Thématique : IMAGERIE Nature : Article DOI : 10.1111/j.1477-9730.2011.00646.x date de publication en ligne : 14/09/2011 En ligne : https://doi.org/10.1111/j.1477-9730.2011.00646.x Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=31164 [article]

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Visibility prediction based on artificial neural networks used in automatic network design / M. Saadatseresht in Photogrammetric record, vol 22 n° 120 (December 2007 - February 2008)

Public [article]  inPhotogrammetric record > vol 22 n° 120 (December 2007 - February 2008) . - pp 336 - 355 Titre : Visibility prediction based on artificial neural networks used in automatic network design Type de document : Article/Communication Auteurs : M. Saadatseresht, Auteur ; M. Varshosaz, Auteur Année de publication : 2007 Article en page(s) : pp 336 - 355 Note générale : Bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Photogrammétrie numérique [Termes descripteurs IGN] apprentissage automatique [Termes descripteurs IGN] incertitude des données [Termes descripteurs IGN] photogrammétrie terrestre [Termes descripteurs IGN] réseau neuronal artificiel [Termes descripteurs IGN] visibilité Résumé : (Auteur) Automatic design of photogrammetric networks is a complex task for which the visibility and quality constraints need to be both modelled and satisfied simultaneously. The task becomes even more complex when measurements are carried out for the first time on a large and/or complex object surrounded by multiple obstructions in a confined workspace. In this situation, automatic visibility prediction of a target point becomes an extremely difficult task. The visibility information inherent within the initial photogrammetric network can be used to solve this problem. However, this introduces some uncertainty into the prediction result because of the incompleteness of the visibility information. In a previous study, the authors developed an analytical deterministic method, visibility uncertainty prediction (VUP), that used ‘‘visibility spheres’’ to predict the visibility of target points. This paper investigates the use of artificial neural networks (ANNs) in visibility prediction, and presents a new technique, ANN-based visibility uncertainty prediction (AVUP), that works by training a feed-forward multi-layer ANN. The visibility data for this network is extracted from the initial photogrammetric network. Once trained, the network can be used to predict the visibility of any target point from a potential camera station. Various experiments were carried out to evaluate the proposed technique. The results showed that, compared to the previous deterministic method, it is more accurate and has a lower computational cost. Copyright RS&PS + Blackwell Publishing Numéro de notice : A2007-569 Thématique : IMAGERIE Nature : Article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=28932 [article]

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