Search results for " Computer science"
showing 10 items of 3983 documents
Towards an XML Adaptation/Alteration Control Framework
2010
International audience
Perception for Robotics: Part II
2019
«What is around me?»knowing how to answer to this question is essential for a robot to navigate safely in its environment. In this part, we will try to find some answers by introducing some tools for helping the robot to perceive the world. Thus, we will present different sensors (lasers, radars, cameras, RGBD sensors) which allow to build a 3D map of the scene where the robot is navigating. Then, we will mainly focus on cameras since these sensors give a rich information about the scene. We will see how we can extract features from the image in order to provide a 3D perception of the world. This chapter presents the main concepts required to start computer vision applied to robotics. It is…
Deep Reinforcement Learning with Omnidirectional Images: application to UAV Navigation in Forests
2022
Deep Reinforcement Learning (DRL) is highly efficient for solving complex tasks such as drone obstacle avoidance using cameras. However, these methods are often limited by the camera perception capabilities. In this paper, we demonstrate that point-goal navigation performances can be improved by using cameras with a wider Field-Of-View (FOV). To this end, we present a DRL solution based on equirectangular images and demonstrates its relevance, especially compared to its perspective version. Several visual modalities are compared: ground truth depth, RGB, and depth directly estimated from these 360°R GB images using Deep Learning methods. Next, we propose a spherical adaptation to take into …
On Keyframe Positioning for Pose Graphs Applied to Visual SLAM
2013
International audience; In this work, a new method is introduced for localization and keyframe identification to solve a Simultaneous Localization and Mapping (SLAM) problem. The proposed approach is based on a dense spherical acquisition system that synthesizes spherical intensity and depth images at arbitrary locations. The images are related by a graph of 6 degrees-of-freedom (DOF) poses which are estimated through spherical registration. A direct image-based method is provided to estimate pose by using both depth and color information simultaneously. A new keyframe identification method is proposed to build the map of the environment by using the covariance matrix between raletive 6 DOF…
Time to Contact Estimation on Paracatadioptric Cameras
2012
International audience; Time to contact or time to collision (TTC) is the time available to a robot before reaching an object. In this paper, we propose to estimate this time using a catadioptric camera embedded on th erobot. Indeed, whereas a lot of works have shown the utility of this kind of cameras in robotic applications (monitoring, locali- sation, motion,...), a few works deal with the problem of time to contact estimation on it. Thus, in this paper, we propose a new work which allows to define and to estimate the TTC on catadioptric camera. This method will be validated on simulated and real data.
Localisation Basée Vision : de l'hétérogénéité des approches et des données
2017
National audience; De nos jours, nous disposons d'une grande diversité de données sur les lieux qui nous entourent. Ces données peuvent être de natures très différentes : une collection d'images, un modèle 3D, un nuage de points colorisés, etc. Lorsque les GPS font défaut, ces informations peuvent être très utiles pour localiser un agent dans son environnement s'il peut lui-même acquérir des informations à partir d'un système de vision. On parle alors de Localisation Basée Vision (LBV). De par la grande hétérogénéité des données acquises et connues sur l'environnement, il existe de nombreux travaux traitant de ce problème. Cet article a pour objet de passer en revue les différentes méthodes…
Reconstruction 3D de scènes dynamiques par segmentation au sens du mouvement
2016
National audience; L'objectif de ce travail est de reconstruire les parties sta-tiques et dynamiques d'une scène 3D à l'aide d'un robot mobile équipé d'un capteur 3D. Cette reconstruction né-cessite la classification des points 3D acquis au cours du temps en point fixe et point mobile indépendamment du dé-placement du robot. Notre méthode de segmentation utilise directement les données 3D et étudie les mouvements des objets dans la scène sans hypothèse préalable. Nous déve-loppons un algorithme complet reconstruisant les parties fixes de la scène à chaque acquisition à l'aide d'un RAN-SAC qui ne requiert que 3 points pour recaler les nuages de points. La méthode a été expérimentée sur de la…
Scheduling coupled-tasks with incompatibility constraint: a bin-packing related problem
2014
International audience; We tackle the makespan minimization problem of coupled- tasks in presence of compatibility constraint. In particular, we focus on stretched coupled-tasks, i.e. coupled-tasks having the same sub-tasks execution time and idle time duration. We show the relationship with bin packing problems for some configurations, and study several problems in framework of complexity and approximation for which the topology of the compatibility graph is specific (star, chain, bipartite, . . .).
Pre-processings and Linear-Decomposition Algorithm to Solve the k-Colorability Problem
2004
International audience; We are interested in the graph coloring problem. We studied the effectiveness of some pre-processings that are specific to the k-colorability problem and that promise to reduce the size or the difficulty of the instances. We propose to apply on the reduced graph an exact method based on a linear-decomposition of the graph. We present some experiments performed on literature instances, among which DIMACS library instances.
Tourism-km: A variant of MMKP applied to the tourism domain
2012
International audience; We are interested in an original real-world problem coming from tourism field. We describe a modelling of the problem and propose a first approach that mixes knowledge management and operational research methods. Our algorithms have been implemented in order to produce tourism solutions that are not unique for a given request but that take into account the preferences of the tourist user and provide a personalized solution. We report computational results obtained on real-world instances.