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Detecting and correcting motion blur from images shot with channel-dependent exposure time / Lâmân Lelégard in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol I-3 (2012)  

Public [article]  inISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol I-3 (2012) . - pp 341 - 346 Titre : Detecting and correcting motion blur from images shot with channel-dependent exposure time Type de document : Article/Communication Auteurs : Lâmân Lelégard , Auteur ; Emeric Delaygue, Auteur ; Mathieu Brédif , Auteur ; Bruno Vallet , Auteur Année de publication : 2012 Conférence : ISPRS 2012, Commission 3, 22th international congress 25/08/2012 01/09/2012 Melbourne Australie OA ISPRS Annals Commission 3 Article en page(s) : pp 341 - 346 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] détection de flou [Termes IGN] image aérienne [Termes IGN] image floue [Termes IGN] image multibande [Termes IGN] restauration d'image [Termes IGN] transformation de Fourier Résumé : (auteur) This article describes a pipeline developed to automatically detect and correct motion blur due to the airplane motion in aerial images provided by a digital camera system with channel-dependent exposure times. Blurred images show anisotropy in their Fourier Transform coefficients that can be detected and estimated to recover the characteristics of the motion blur. To disambiguate the anisotropy produced by a motion blur from the possible spectral anisotropy produced by some periodic patterns present in a sharp image, we consider the phase difference of the Fourier Transform of two channel shot with different exposure times (i.e. with different blur extensions). This is possible because of the deep correlation between the three visible channels ensures phase coherence of the Fourier Transform coefficients in sharp images. In this context, considering the phase difference constitutes both a good detector and estimator of the motion blur parameters. In order to improve on this estimation, the phase difference is performed on local windows in the image where the channels are more correlated. The main lobe of the phase difference, where the phase difference between two channels is close to zero actually imitates an ellipse which axis ratio discriminates blur and which orientation and minor axis give respectively the orientation and the blur kernel extension of the long exposure-time channels. However, this approach is not robust to the presence in the phase difference of minor lobes due to phase sign inversions in the Fourier transform of the motion blur. They are removed by considering the polar representation of the phase difference. Based on the blur detection step, blur correction is eventually performed using two different approaches depending on the blur extension size: using either a simple frequency-based fusion for small blur or a semi blind iterative method for larger blur. The higher computing costs of the latter method make it only suitable for large motion blur, when the former method is not applicable. Numéro de notice : A2012-709 Affiliation des auteurs : LASTIG MATIS+Ext (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprsannals-I-3-341-2012 En ligne : http://dx.doi.org/10.5194/isprsannals-I-3-341-2012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82688 [article]

Trajectory-based registration of 3d lidar point clouds acquired with a mobile mapping system / Adrien Gressin in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol I-3 (2012)  

Public [article]  inISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol I-3 (2012) . - pp 117 - 122 Titre : Trajectory-based registration of 3d lidar point clouds acquired with a mobile mapping system Type de document : Article/Communication Auteurs : Adrien Gressin , Auteur ; Bertrand Cannelle , Auteur ; Clément Mallet , Auteur ; Jean-Pierre Papelard , Auteur Année de publication : 2012 Conférence : ISPRS 2012, Commission 3, 22th international congress 25/08/2012 01/09/2012 Melbourne Australie OA ISPRS Annals Commission 3 Article en page(s) : pp 117 - 122 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] algorithme ICP [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] semis de points [Termes IGN] système de numérisation mobile [Termes IGN] traitement de données localisées [Termes IGN] trajectoire (véhicule non spatial) Résumé : (auteur) Thanks to a hybrid georeferencing unit coupling GNSS and IMU sensors, mobile mapping systems (MMS) with lidar sensors provide accurate 3D point clouds of the acquired areas, mainly urban cities. When dealing with several acquisitions of the same area with the same device, differences in the range of several tens of centimeters can be observed. Such degradation of the georeferencing accuracies are due to two main reasons: inertial drift and losses of GNSS signals in urban corridors. The purpose of this paper is therefore to correct these differences with an accurate ICP-based registration algorithm, and then to correct the MMS trajectory using these retrieved local transformation parameters.The trajectory loop information plays a key role for that purpose. We propose a four-step method starting from a 3D point cloud with overlapping parts, and the trajectory of the mobile mapping system. First, a polygonal approximation of the trajectory is computed in order to first divide the whole registration problem in local sub-issues. Secondly, we aim to find all the potential overlapping acquired areas between these segments using simple bounding box intersections. Thirdly, for each pair of overlapping areas, an efficient variant of the ICP algorithm is proposed to (1) prune cases where segments do not share point clouds of the same areas and (2) retrieve the transformation parameters, for real overlapping cases. Finally, all these transformations are linked together, and fed into a global distance compensation problem, allowing to adjust the MMS trajectories for several passages. As a conclusion, this method is successfully applied to data acquired over Paris (France) with the Stereopolis mobile mapping system. Numéro de notice : A2012-711 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprsannals-I-3-117-2012 Date de publication en ligne : 20/07/2012 En ligne : http://dx.doi.org/10.5194/isprsannals-I-3-117-2012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82700 [article]

Improving 3D lidar point cloud registration using optimal neighborhood knowledge / Adrien Gressin in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol I-3 (2012)  

Public [article]  inISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol I-3 (2012) . - pp 111 - 116 Titre : Improving 3D lidar point cloud registration using optimal neighborhood knowledge Type de document : Article/Communication Auteurs : Adrien Gressin , Auteur ; Clément Mallet , Auteur ; Nicolas David , Auteur Année de publication : 2012 Projets : 1-Pas de projet / Conférence : ISPRS 2012, Commission 3, 22th international congress 25/08/2012 01/09/2012 Melbourne Australie OA ISPRS Annals Commission 3 Article en page(s) : pp 111 - 116 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] algorithme ICP [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] semis de points [Termes IGN] superposition de données [Termes IGN] tenseur [Termes IGN] valeur propre [Termes IGN] voisinage (relation topologique) Résumé : (auteur) Automatic 3D point cloud registration is a main issue in computer vision and photogrammetry. The most commonly adopted solution is the well-known ICP (Iterative Closest Point) algorithm. This standard approach performs a fine registration of two overlapping point clouds by iteratively estimating the transformation parameters, and assuming that good a priori alignment is provided. A large body of literature has proposed many variations of this algorithm in order to improve each step of the process. The aim of this paper is to demonstrate how the knowledge of the optimal neighborhood of each 3D point can improve the speed and the accuracy of each of these steps. We will first present the geometrical features that are the basis of this work. These low-level attributes describe the shape of the neighborhood of each 3D point, computed by combining the eigenvalues of the local structure tensor. Furthermore, they allow to retrieve the optimal size for analyzing the neighborhood as well as the privileged local dimension (linear, planar, or volumetric). Besides, several variations of each step of the ICP process are proposed and analyzed by introducing these features. These variations are then compared on real datasets, as well with the original algorithm in order to retrieve the most efficient algorithm for the whole process. Finally, the method is successfully applied to various 3D lidar point clouds both from airborne, terrestrial and mobile mapping systems. Numéro de notice : A2012-712 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprsannals-I-3-111-2012 En ligne : http://dx.doi.org/10.5194/isprsannals-I-3-111-2012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82701 [article]

Building edge detection using small-footprint airborne full-waveform lidar data / Jean-Christophe Michelin in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol I-3 (2012)  

Public [article]  inISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol I-3 (2012) . - pp 147 - 152 Titre : Building edge detection using small-footprint airborne full-waveform lidar data Type de document : Article/Communication Auteurs : Jean-Christophe Michelin , Auteur ; Clément Mallet , Auteur ; Nicolas David , Auteur Année de publication : 2012 Projets : 1-Pas de projet / Conférence : ISPRS 2012, Commission 3, 22th international congress 25/08/2012 01/09/2012 Melbourne Australie OA ISPRS Annals Commission 3 Article en page(s) : pp 147 - 152 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] détection de contours [Termes IGN] données lidar [Termes IGN] données localisées 3D [Termes IGN] empreinte [Termes IGN] forme d'onde pleine [Termes IGN] modèle physique [Termes IGN] précision planimétrique [Termes IGN] reconnaissance de formes [Termes IGN] zone urbaine Résumé : (auteur) The full-waveform lidar technology allows a complete access to the information related to the emitted and backscattered laser signals. Although most of the common applications of full-waveform lidar are currently dedicated to the study of forested areas, some recent studies have shown that airborne full-waveform data is relevant for urban area analysis. We extend the field to pattern recognition with a focus on retrieval. Our proposed approach combines two steps. In a first time, building edges are coarsely extracted. Then, a physical model based on the lidar equation is used to retrieve a more accurate position of the estimated edge than the size of the lidar footprint. Another consequence is the estimation of more accurate planimetric positions of the extracted echoes. Numéro de notice : A2012-713 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprsannals-I-3-147-2012 En ligne : http://dx.doi.org/10.5194/isprsannals-I-3-147-2012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82702 [article]

Off-line vs. On-line calibration of a panoramic-based mobile mapping system / Bertrand Cannelle in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol I-3 (2012)  

Public [article]  inISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol I-3 (2012) . - pp 31 - 36 Titre : Off-line vs. On-line calibration of a panoramic-based mobile mapping system Type de document : Article/Communication Auteurs : Bertrand Cannelle , Auteur ; Nicolas Paparoditis , Auteur ; Marc Pierrot-Deseilligny , Auteur ; Jean-Pierre Papelard , Auteur Année de publication : 2012 Article en page(s) : pp 31 - 36 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Acquisition d'image(s) et de donnée(s) [Termes IGN] centrale inertielle [Termes IGN] chambre DTC [Termes IGN] étalonnage d'instrument [Termes IGN] étalonnage de capteur (imagerie) [Termes IGN] étalonnage en vol [Termes IGN] précision submillimétrique Résumé : (auteur) This paper presents two methods to calibrate a photogrammetric-based mobile mapping system. The paper is organised as follow. The first part presents the problem we are trying to solve, i.e. the calibration of multi-camera head on a mobile mapping system equipped with an Inertial Navigation System (INS). We want to estimate on the one hand the relative pose of images within the head and on the other hand the relative pose between the head and the INS. The second part presents the first calibration method which is based on observations of a sub-millimeter accuracy topometric target network. The third part explores a method to determine the calibration on-line, i.e. using the images acquired during the surveys. The final section compare the two methods on an neutral data set and resumes the pros and cons of each method. Numéro de notice : A2012-714 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprsannals-I-3-31-2012 En ligne : http://dx.doi.org/10.5194/isprsannals-I-3-31-2012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=82703 [article]

Extraction of vineyards out of aerial photo-image using texture information / Arnaud Le Bris in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol I-3 (2012)  

Public [article]  inISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol I-3 (2012) . - pp 383 - 388 Titre : Extraction of vineyards out of aerial photo-image using texture information Type de document : Article/Communication Auteurs : Arnaud Le Bris , Auteur Année de publication : 2012 Conférence : ISPRS 2012, Commission 3, 22th international congress 25/08/2012 01/09/2012 Melbourne Australie OA ISPRS Annals Commission 3 Article en page(s) : pp 383 - 388 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] détection automatique [Termes IGN] occupation du sol [Termes IGN] orthoimage [Termes IGN] SIFT (algorithme) [Termes IGN] transformation de Fourier [Termes IGN] viticulture Résumé : (auteur) A cartography of vineyards is required by many mapping agencies, both to draw topographic maps and to complete the "vineyard" layer of large scale land cover databases. In this paper, two distinct approaches are proposed and tested to achieve a (semi-)automatic detection of vineyards task out of 50cm ground resolution ortho-images. Both are object based approaches relying on image texture analysis in homogeneous land cover regions. Therefore, the first step (common to both approaches) is a segmentation of the image into homogeneous land cover regions. These regions can then be classified as vineyards or not by the next approaches. A first approach consists in a frequency analysis of the image texture in each region. A semi-variogram is first calculated from the ortho-image for each region of the segmentation. A Fourier transform (FFT) of this semi-variogram of the image is then considered. If a periodic signal with a high frequency (i.e. of which the frequency is upper than a threshold) is identified, the region is labelled as a vineyard. The second approach is a supervised (per region) land cover classification one. It uses texture indexes calculated from ortho-images as input image information. In particular, some texture indexes derived from SIFT descriptors calculated from ortho-images have been used in the experiments, giving good results. Numéro de notice : A2012-761 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprsannals-I-3-383-2012 Date de publication en ligne : 23/07/2012 En ligne : https://doi.org/10.5194/isprsannals-I-3-383-2012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101199 [article]

Streamed vertical rectangle detection in terrestrial laser scans for facade database / Jérôme Demantké in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol I-3 (2012)  

Public [article]  inISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol I-3 (2012) . - pp 99 - 104 Titre : Streamed vertical rectangle detection in terrestrial laser scans for facade database Type de document : Article/Communication Auteurs : Jérôme Demantké , Auteur ; Bruno Vallet , Auteur ; Nicolas Paparoditis , Auteur Année de publication : 2012 Article en page(s) : pp 99 - 104 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Traitement d'image optique [Termes IGN] chevauchement [Termes IGN] détection d'objet [Termes IGN] échantillonnage de données [Termes IGN] façade [Termes IGN] fusion d'images [Termes IGN] Ransac (algorithme) [Termes IGN] reconnaissance de formes Résumé : (auteur) A reliable and accurate facade database would be a major asset in applications such as localization of autonomous vehicles, registration and fine building modeling. Mobile mapping devices now provide the data required to create such a database, but efficient methods should be designed in order to tackle the enormous amount of data collected by such means (a million point per second for hours of acquisition). Another important limitation is the presence of numerous objects in urban scenes of many different types. This paper proposes a method that overcomes these two issues: • The facade detection algorithm is streamed : the data is processed in the order it was acquired. More precisely, the input data is split into overlapping blocks which are analysed in turn to extract facade parts. Close overlapping parts are then merged in order • The geometry of the neighborhood of each point is analysed to define a probability that the point belongs to a vertical planar patch. This probability is then injected in a RANdom SAmple Consensus (RANSAC) algorithm both in the sampling step and in the hypothesis validation, in order to favour the most reliable candidates. This ensures much more robustness against outliers during the facade detection. This way, the main vertical rectangles are detected without any prior knowledge about the data. The only assumptions are that the facades are roughly planar and vertical. The method has been successfully tested on a large dataset in Paris. The facades are detected despite the presence of trees occluding large areas of some facades. The robustness and accuracy of the detected facade rectangles makes them useful for localization applications and for registration of other scans of the same city or of entire city models. Numéro de notice : A2012-763 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprsannals-I-3-99-2012 Date de publication en ligne : 20/07/2012 En ligne : https://doi.org/10.5194/isprsannals-I-3-99-2012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101275 [article]

Trees detection from laser point clouds acquired in dense urban areas by a mobile mapping system / Fabrice Monnier in ISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences, vol I-3 (2012)  

Public [article]  inISPRS Annals of the Photogrammetry, Remote Sensing and Spatial Information Sciences > vol I-3 (2012) . - pp 245 - 250 Titre : Trees detection from laser point clouds acquired in dense urban areas by a mobile mapping system Type de document : Article/Communication Auteurs : Fabrice Monnier , Auteur ; Bruno Vallet , Auteur ; Bahman Soheilian , Auteur Année de publication : 2012 Article en page(s) : pp 245 - 250 Note générale : bibliographie Langues : Anglais (eng) Descripteur : [Vedettes matières IGN] Lasergrammétrie [Termes IGN] analyse de groupement [Termes IGN] détection d'arbres [Termes IGN] détection de partie cachée [Termes IGN] données lidar [Termes IGN] Ransac (algorithme) [Termes IGN] reconstruction 3D [Termes IGN] scène urbaine [Termes IGN] semis de points [Termes IGN] système de numérisation mobile Résumé : (auteur) 3D reconstruction of trees is of great interest in large-scale 3D city modelling. Laser scanners provide geometrically accurate 3D point clouds that are very useful for object recognition in complex urban scenes. Trees often cause important occlusions on building façades. Their recognition can lead to occlusion maps that are useful for many façade oriented applications such as visual based localisation and automatic image tagging. This paper proposes a pipeline to detect trees in point clouds acquired in dense urban areas with only laser informations (x,y, z coordinates and intensity). It is based on local geometric descriptors computed on each laser point using a determined neighbourhood. These descriptors describe the local shape of objects around every 3D laser point. A projection of these values on a 2D horizontal accumulation space followed by a combination of morphological filters provides individual tree clusters. The pipeline is evaluated and the results are presented on a set of one million laser points using a man made ground truth. Numéro de notice : A2012-764 Affiliation des auteurs : LASTIG MATIS (2012-2019) Thématique : IMAGERIE Nature : Article nature-HAL : ArtAvecCL-RevueIntern DOI : 10.5194/isprsannals-I-3-245-2012 Date de publication en ligne : 20/07/2012 En ligne : https://doi.org/10.5194/isprsannals-I-3-245-2012 Format de la ressource électronique : URL article Permalink : https://documentation.ensg.eu/index.php?lvl=notice_display&id=101276 [article]