Ré-identification de personnes : application aux réseaux de caméras à champs disjoints

Cette thèse s'inscrit dans le contexte de la vidéosurveillance "intelligente", et s'intéresse à la supervision de réseaux de caméras à champs disjoints, contrainte classique lorsque l'on souhaite limiter l'instrumentation du bâtiment. Il s'agit là de l'un des cas d'application du problème de la ré-identification de personnes. À ce titre, la thèse propose une approche se démarquant de l'état de l'art qui traite classiquement le problème sous l'aspect description, via la mise en correspondance de signatures image à image. Nous l'abordons ici sous l'aspect filtrage : comment intégrer la ré-identification de personne dans un processus de suivi multi-pistes, de manière à maintenir des identités de pistes cohérentes, malgré des discontinuités dans l'observation. Nous considérons ainsi une approche suivi et mises en correspondance, au niveau caméra et utilisons ce module pour ensuite raisonner au niveau du réseau. Nous décrivons dans un premier temps les approches classiques de ré-identification, abordées sous l'aspect description. Nous proposons ensuite un formalisme de filtrage particulaire à états continus et discret pour estimer conjointement position et identité de la cible au cours du temps, dans chacune des caméras. Un second étage de traitement permet d'intégrer la topologie du réseau et les temps d'apparition pour optimiser la ré-identification au sein du réseau. Nous démontrons la faisabilité de l'approche en grande partie sur des données issues de réseaux de caméras déployés au sein du laboratoire, étant donné le manque de données publiques concernant ce domaine. Nous prévoyons de mettre en accès public ces banques de données.This thesis deals with intelligent videosurveillance, and focus on the supervision of camera networks with nonoverlapping fields of view, a classical constraint when it comes to limitate the building instrumentation. It is one of the use-case of the pedestrian re-identification problem. On that point, the thesis distinguishes itself from state of the art methods, which treat the problem from the descriptor perspective through image to image signatures comparison. Here we consider it from a bayesian filtering perspective : how to plug re-identification in a complete multi-target tracking process, in order to maintain targets identities, in spite of observation discontinuities. Thus we consider tracking and signature comparison, at the camera level, and use that module to take decisions at the network level. We describe first the classical re-identification approaches, based on the description. Then, we propose a mixed-state particle filter framework to estimate jointly the targets positions and their identities in the cameras. A second stage of processing integrates the network topology and optimise the re-identifications in the network. Considering the lack of public data in nonoverlapping camera network, we mainly demonstrate our approach on camera networks deployed at the lab. A publication of these data is in progress

Nestehiometrijski bromo-kloro-piridin-MoIII kompleksi

By a selective exchange of ligand Br by Cl, a series of nonstoichiometric bromo-chloro-pyridine- molybdenum(III) octahedral compounds of the type (cat)[MoBraCl(4-a)py2] (cat = pyH, a = 3–1 (1, 4, 7)); cat = [(C2H5)3NH], a = 2.744 (2); cat = Rb, a = 2.278 (5); cat =[(C6H5)4)As], a = 1.258 (8) and [MoBraCl(3–a)py3] (a = 2–1 (3, 6)) have been prepared and characterized. Owing to great similarity of the powder diffraction patterns and IR spectra of compounds mer- [MoBraCl(3-a)py3] (a = 3–0) with the known monoclinic modification in the space group P21/c and compounds [MoBraCl(3-a)py3] (a = 2-1 (3, 6)), the same type of crystal lattice was confirmed. Isostructurality was observed also for the orthorhombic trans-(pyH)[MoBr4py2]](Pnma) and compounds 1 and 4, while compound 7 is isostructural to trans-(pyH)[MoCl4py2]. X-ray crystallographic analyses of 2, 5 and 8, obtained by recrystallization of (pyH)[MoBraCl(4-a)py2] (a = 3–1) with different cations, were performed. In these compounds, MoIII is octahedrally coordinated with four halogenido ions at distances 2.4953(6)–2.5920(10) Å and two pyridine molecules at distances 2.195(4)-2.220(4) Å. Trans oriented pyridine rings in compounds 5 and 8 are co-planar, while deviation from co-planarity was noticed for compound 2 (8.9(3)°). The stoichiometry of four coordinated Br and Cl atoms in these compounds is not ideal, since the structure analysis results for 2, 5 and 8 show a mixed occupancy of crystallographic sites; thus, refined population parameters for both atoms (Br and Cl) were calculated.Selektivnom zamjenom bromovoga liganda klorovim dobijena je i karakterizirana serija nestehiometrijskih bromo-kloro-piridin-MoIII kompleksa tipa (cat)[MoBraCl(4–a)py2] (cat = pyH, a = 3–1 (1, 4, 7); cat = [(C2H5)3NH], a = 2.744 (2); cat = Rb, a = 2.278 (5); cat = [(C6H5)4As], a = 1.258 (8)) i [MoBraCl(3–a)py3] (a = 2–1 (3, 6)). Uslijed velike sličnosti difraktograma praha i IR spektara spojeva mer-[MoBraCl(3–a)py3] (a = 3–0) poznate monoklinske modifikacije u prostornoj grupi P21/c i spojeva [MoBraCl(3–a)py3] (a = 2–1 (3, 6)), potvr|en je isti tip kristalne re{etke. Opa`ena je izostrukturnost rompskoga trans-(pyH)[MoBr4py2] (Pnma) i spojeva 1 i 4, dok je spoj 7 izostrukturiran s trans-(pyH)[MoCl4py2]. Načinjena je rentgenska strukturna analiza spojeva 2, 5 i 8 dobijenih prekristalizacijom (pyH)[MoBraCl(4–a)py2] (a = 3–1) s različitim kationima. U tim je spojevima MoIII oktaedarski koordiniran s četiri halogenidna iona na udaljenostima 2.4953(6)–2.5920(10) Å i dvije molekule piridina na udaljenostima 2.195(4)–2.220(4) Å. Trans orijentirani piridinski prstenovi u spojevima 5 i 8 su koplanarni dok je kod spoja 2 ustanovljena devijacija od koplanarnosti (8.9(3)°). Strukturnom analizom utočnjeni su faktori zauzetosti četiri koordinirana atoma (Br, Cl) u spojevima 2, 5 i 8. Na|eno je da su navedeni kristalografski položaji zauzeti atomima Cl i Br u nestehiometrijskome omjeru

Nestehiometrijski bromo-kloro-piridin-MoIII kompleksi

By a selective exchange of ligand Br by Cl, a series of nonstoichiometric bromo-chloro-pyridine- molybdenum(III) octahedral compounds of the type (cat)[MoBraCl(4-a)py2] (cat = pyH, a = 3–1 (1, 4, 7)); cat = [(C2H5)3NH], a = 2.744 (2); cat = Rb, a = 2.278 (5); cat =[(C6H5)4)As], a = 1.258 (8) and [MoBraCl(3–a)py3] (a = 2–1 (3, 6)) have been prepared and characterized. Owing to great similarity of the powder diffraction patterns and IR spectra of compounds mer- [MoBraCl(3-a)py3] (a = 3–0) with the known monoclinic modification in the space group P21/c and compounds [MoBraCl(3-a)py3] (a = 2-1 (3, 6)), the same type of crystal lattice was confirmed. Isostructurality was observed also for the orthorhombic trans-(pyH)[MoBr4py2]](Pnma) and compounds 1 and 4, while compound 7 is isostructural to trans-(pyH)[MoCl4py2]. X-ray crystallographic analyses of 2, 5 and 8, obtained by recrystallization of (pyH)[MoBraCl(4-a)py2] (a = 3–1) with different cations, were performed. In these compounds, MoIII is octahedrally coordinated with four halogenido ions at distances 2.4953(6)–2.5920(10) Å and two pyridine molecules at distances 2.195(4)-2.220(4) Å. Trans oriented pyridine rings in compounds 5 and 8 are co-planar, while deviation from co-planarity was noticed for compound 2 (8.9(3)°). The stoichiometry of four coordinated Br and Cl atoms in these compounds is not ideal, since the structure analysis results for 2, 5 and 8 show a mixed occupancy of crystallographic sites; thus, refined population parameters for both atoms (Br and Cl) were calculated.Selektivnom zamjenom bromovoga liganda klorovim dobijena je i karakterizirana serija nestehiometrijskih bromo-kloro-piridin-MoIII kompleksa tipa (cat)[MoBraCl(4–a)py2] (cat = pyH, a = 3–1 (1, 4, 7); cat = [(C2H5)3NH], a = 2.744 (2); cat = Rb, a = 2.278 (5); cat = [(C6H5)4As], a = 1.258 (8)) i [MoBraCl(3–a)py3] (a = 2–1 (3, 6)). Uslijed velike sličnosti difraktograma praha i IR spektara spojeva mer-[MoBraCl(3–a)py3] (a = 3–0) poznate monoklinske modifikacije u prostornoj grupi P21/c i spojeva [MoBraCl(3–a)py3] (a = 2–1 (3, 6)), potvr|en je isti tip kristalne re{etke. Opa`ena je izostrukturnost rompskoga trans-(pyH)[MoBr4py2] (Pnma) i spojeva 1 i 4, dok je spoj 7 izostrukturiran s trans-(pyH)[MoCl4py2]. Načinjena je rentgenska strukturna analiza spojeva 2, 5 i 8 dobijenih prekristalizacijom (pyH)[MoBraCl(4–a)py2] (a = 3–1) s različitim kationima. U tim je spojevima MoIII oktaedarski koordiniran s četiri halogenidna iona na udaljenostima 2.4953(6)–2.5920(10) Å i dvije molekule piridina na udaljenostima 2.195(4)–2.220(4) Å. Trans orijentirani piridinski prstenovi u spojevima 5 i 8 su koplanarni dok je kod spoja 2 ustanovljena devijacija od koplanarnosti (8.9(3)°). Strukturnom analizom utočnjeni su faktori zauzetosti četiri koordinirana atoma (Br, Cl) u spojevima 2, 5 i 8. Na|eno je da su navedeni kristalografski položaji zauzeti atomima Cl i Br u nestehiometrijskome omjeru

Suivi par ré-identification dans un réseau de caméras à champs disjoints

Session "Articles"National audienceCet article adresse le problème de suivi automatique de piétons au travers de réseaux de caméras à champs de vue disjoints. Le suivi dans l'image est traité de manière locale par un algorithme de Suivi-par-Détections et ré-identification. Avec du filtrage particulaire à état mixte, nous introduisons la notion d'identité globale dans un algorithme de suivi multi-pistes pour caractériser les personnes au niveau du réseau et pallier aux discontinuités d'observations. Nous venons renforcer la décision de ré-identification en proposant un schéma décisionnel haut niveau intégrant les hypothèses de chaque traqueur confrontées à la topologie du réseau. La composante suivi multi-personnes et ré-identification est d'abord testée en contexte monocaméra. Nous évaluons ensuite notre approche complète sur un réseau de 3 caméras à champs de vue disjoints et un ensemble de 7 personnes. La seule connaissance a priori requise est la carte topologique du réseau

Ré-identification de personnes (application aux réseaux de caméras à champs disjoints)

TOULOUSE3-BU Sciences (315552104) / SudocSudocFranceF

Mixed-State CONDENSATION pour suivi et ré-identification simultanés dans des réseaux de caméras à champs de vue disjoints

National audienceThis article presents a novel approach to person tracking within large-scale environments monitored by nonoverlapping field-of-view camera networks. We address the image-based tracking problem with distributed particle filters using a hierarchical color model. The novelty of our approach resides in the embedding of an already-seenpeople database in the particle filter framework. Doing so, the filter performs not only image position estimation but also does establish identity probabilities for the current targets in the network. Thus we use online person re-identification as a way to introduce continuity to track people in disjoint camera networks. No calibration stage is required. We demonstrate the performances of our approach on a network of 5 disjoint cameras and a 16-person database.Cet article présente une nouvelle approche pour le suivi de personnes par réseau de caméras à champs de vue disjoints. Le problème du suivi dans l'image est traité par des filtres à particules distribués utilisant un modèle de couleurs hiérarchiques. La nouveauté de notre approche réside dans l'insertion d'une base de personnes déjà rencontrées dans le réseau, dans le formalisme du filtre à particule. Ce faisant, les filtres ne réalisent plus seulement une estimation de position dans l'image mais aussi établissent une identité potentielle pour les cibles, relativement à la base de personnes. Ainsi nous envisageons la ré-identification en ligne de personnes pour introduire de la continuité et pouvoir suivre les cibles dans un réseau à champs de vue disjoints. Aucune calibration n'est requise. Nous évaluons notre approche sur un réseau de 5 caméras à champs de vue disjoints et un ensemble de 16 personnes

HSPA: Hough space pattern analysis as an answer to local description ambiguities for 3D pose estimation

When performing feature-based 3D object registration, one may expect to find a unique point corresponding to the right transformation in Hough space for each object instance. However, we observed that description ambiguities of the objects or scenes create a structured pattern in the Hough space of transformations during the matching process. We argue that this pattern can be viewed as a global descriptor, as opposed to the local descriptors or features whose matching resulted in the pattern. Thus, we propose to shift the focus from finding better local descriptors to better using the Hough-space pattern. This paper introduces a methodology to compute, analyze and match said patterns in order to improve the quality of 3D pose estimation. We detail a whole framework, termed HSPA, to first generate what we call the Hough space canonical invariance pattern for any given object to register and second, take this pattern into account when assembling and pruning pose hypotheses generated by a registration algorithm. We show the benefits of this technique on object registration as well as 3D scene registration benchmarks

Tracking-by-reidentification in a non-overlapping fields of view cameras network

International audienceThis article tackles the problem of automatic multi-pedestrian tracking in non-overlapping fields of view camera networks, using monocular, uncalibrated cameras. Tracking is locally addressed by a Tracking-by-Detection and reidentification algorithm. We propose here to introduce the concept of global identity into a multi-target tracking algorithm, qualifying people at the network level, to allow us to rebound observation dis-continuities. We embed that identity into the tracking loop thanks to the mixed-state particle filter framework, thus including it in the search space. Doing so, each tracker maintains a mutli-modality on the identity in the network of its target. We increase the decision strength introducing a high level decision scheme which integrates all the trackers hypothesis over all the cameras of the network with previous reidentification results and the topology of the network. The tracking and reidentification module is first tested with a single camera. We then evaluate the whole framework on a 3 non-overlapping fields of view network with 7 identities. The only a priori knowledge assumed is a topological map of the network

Tracking Objects of Interest Through a Camera Network, in Intelligent Video Surveillance Systems, DUFOUR,J-Y (Ed)

Belonging to the wider academic field of computer vision, video analytics has aroused a phenomenal surge of interest since the current millennium. Video analytics is intended to solve the problem of the incapability of exploiting video streams in real time for the purpose of detection or anticipation. It involves analyzing the videos using algorithms that detect and track objects of interest over time and that indicate the presence of events or suspect behavior involving these objects. The aims of this book are to highlight the operational attempts of video analytics, to identify possible driving forces behind potential evolutions in years to come, and above all to present the state of the art and the technological hurdles which have yet to be overcome. The need for video surveillance is introduced through two major applications (the security of rail transportation systems and a posteriori investigation). The characteristics of the videos considered are presented through the cameras which enable capture and the compression methods which allow us to transport and store them. Technical topics are then discussed - the analysis of objects of interest (detection, tracking and recognition), 'high-level' video analysis, which aims to give a semantic interpretation of the observed scene (events, behaviors, types of content). The book concludes with the problem of performance evaluation

Suivi d'objets d'intérêt dans un réseau de caméras, in Outils d'analyse vidéo : Pour une pleine exploitation des données de vidéoprotection, DUFOUR, JY (ED)

L'utilisation croissante de la vidéoprotection rend nécessaire la mise en place de fonctions d'analyse vidéo pour alléger voire automatiser des tâches aujourd'hui entièrement réalisées par des opérateurs. Après avoir dressé un panorama des avancées et des perspectives en analyse d'image, cet ouvrage détaille les principales fonctions d'analyse vidéo, comme la détection, le suivi et la reconnaissance d'objets d'intérêt (personnes ou véhicules) ou les fonctions de « haut-niveau » visant à interpréter les scènes observées (évènements, comportements, nature de la scène...). Les besoins sont illustrés sous l'angle de deux applications majeures, la sécurité des transports et l'investigation. Les contraintes d'ordres juridique et éthique sont présentées, ainsi que les caractéristiques des données vidéo traitées, au travers des caméras et des méthodes de compression utilisées. La problématique de l'évaluation de performance, tant au niveau opérationnel qu'au niveau des fonctions d'analyse, est également exposée