Cadre générique pour le recalage dense combinant un coût dense et et un coût basé sur des correspondances de primitives

National audienceL'estimation dense de correspondances entre deux images est un sujet essentiel de la vision par ordinateur et s'exprime sous plusieurs formes : déformations rigides ou flexibles avec de faibles ou grandes amplitudes de déplacements. De nombreuses solutions spécifiques existent mais aucune méthodologie unifiée n'a été formulée. Cet article propose une nouvelle approche générale qui combine de manière robuste un coût dense par pixel et un coût basé sur des correspondances de primitives. Ce dernier utilise une distance robuste permettant d'exploiter des correspondances de points ou de segments. Les correspondances permettent d'empêcher l'optimisation dense de tomber dans un minimum local. En utilisant un coût dense robuste, associé à une régularisation au second ordre et une détection explicite des auto-occultations, nous obtenons des résultats égalant ou surpassant l'état de l'art pour les applications de flot optique 2D, stéréo à fortes disparité et recalage de surfaces déformables. De plus, le faible couplage des modules permet une grande flexibilité en fonction de l'application

Hippocampal sclerosis affects fMR-adaptation of lyrics and melodies in songs

Songs constitute a natural combination of lyrics and melodies, but it is unclear whether and how these two song components are integrated during the emergence of a memory trace. Network theories of memory suggest a prominent role of the hippocampus, together with unimodal sensory areas, in the build-up of conjunctive representations. The present study tested the modulatory influence of the hippocampus on neural adaptation to songs in lateral temporal areas. Patients with unilateral hippocampal sclerosis and healthy matched controls were presented with blocks of short songs in which lyrics and/or melodies were varied or repeated in a crossed factorial design. Neural adaptation effects were taken as correlates of incidental emergent memory traces. We hypothesized that hippocampal lesions, particularly in the left hemisphere, would weaken adaptation effects, especially the integration of lyrics and melodies. Results revealed that lateral temporal lobe regions showed weaker adaptation to repeated lyrics as well as a reduced interaction of the adaptation effects for lyrics and melodies in patients with left hippocampal sclerosis. This suggests a deficient build-up of a sensory memory trace for lyrics and a reduced integration of lyrics with melodies, compared to healthy controls. Patients with right hippocampal sclerosis showed a similar profile of results although the effects did not reach significance in this population. We highlight the finding that the integrated representation of lyrics and melodies typically shown in healthy participants is likely tied to the integrity of the left medial temporal lobe. This novel finding provides the first neuroimaging evidence for the role of the hippocampus during repetitive exposure to lyrics and melodies and their integration into a song

Caméras virtuelles pour la calibration d'un système de réalité augmentée composé d'un écran transparent et deux caméras à champs disjoints

National audienceUne nouvelle méthode de calibration extrinsèque pour systèmes de réalité augmentée sur affichages transparents est proposée. Elle est principalement destinée à un système composé d'un écran semi-transparent, d'une caméra de suivi de l'utilisateur et d'une autre caméra, à champ dis- joints, pour localiser le système au sein de l'environne- ment mais facilement généralisable. L'algorithme se base sur des indications fournies par l'utilisateur sur la projection apparente sur l'écran de points de référence d'un objet connu. Une estimation convexe est calculée grâce à la calibration de caméras virtuelles et sert d'initialisation à un ajustement de faisceaux global. Des expériences sur données synthétiques et réelles montrent le bien-fondé de cette approche. Ceci est une traduction de la publication originale

Detection of a large valley-orbit splitting in silicon with two-donor spectroscopy

We measure a large valley-orbit splitting for shallow isolated phosphorus donors in a silicon gated nanowire. This splitting is close to the bulk value and well above previous reports in silicon nanostructures. It was determined using a double dopant transport spectroscopy which eliminates artifacts induced by the environment. Quantitative simulations taking into account the position of the donors with respect to the Si/SiO$_2$ interface and electric field in the wire show that the values found are consistent with the device geometry

Modélisation explicite des objets et de l'environnement en combinant les approches topologique et métrique pour la localisation

Session: SLAM et localisation - http://orasis2011.inrialpes.fr/programmeNational audienceThis paper presents a new formulation of place recognition in unknown environments. Many objects in indoor environments are likely to be moved. We want to make the most of several observations of a camera in the same scene to represent the different places and objects. We propose to combine methods of metrical and topological localization to detect and model objects. We present also a probabilistic approach for place recognition that considers the objects.Nous présentons dans cet article une nouvelle formulation de la modélisation et de la reconnaissance de lieu. Les milieux intérieurs sont composés d'une quantité d'objets susceptibles d'être déplacés. Nous souhaitons exploiter les multiples passages d'une caméra dans un même environnement pour modéliser d'une part la structure de la scène et d'autre part les objets le constituant. Nous proposons une association de méthodes de SLAM métrique et topologique pour détecter et représenter les objets, ainsi qu'un formalisme probabiliste pour la reconnaissance de lieu prenant en compte l'évolution des objets

Détection et apprentissage automatique d'objets pour la modélisation de milieux intérieurs

Session "Posters" - Site conf.: http://liris.cnrs.fr/rfia2012National audienceNous présentons dans cet article une nouvelle méthode pour la modélisation des objets et de la scène dans un environnement intérieur inconnu. Les milieux intérieurs sont composés d'une quantité d'objets susceptibles d'être déplacés. Nous souhaitons exploiter les multiples passages d'une caméra dans un même lieu et tirer parti de ces déplacements pour modéliser d'une part la structure de la scène et d'autre part les objets le constituant. Nous proposons une association de méthodes de SLAM métrique et de reconnaissance de lieu pour détecter et représenter les objets de façon automatique et enrichir la connaissance de la scène. Abstract: This paper presents a new solution for modeling the scene and the objects in unknown environments. Many objects in indoor environments are likely to be moved. We want to make the most of several observations of a camera in the same scene to represent the different places and objects. We propose to combine methods of metrical localization and place recognition to detect and model objects and extend the scene model

Hidden progress: broadband plasmonic invisibility

The key challenge in current research into electromagnetic cloaking is to achieve invisibility over an extended bandwidth. There has been significant progress towards this using the idea of cloaking by sweeping under the carpet of Li and Pendry, with dielectric structures superposed on a mirror. Here, we show that we can harness surface plasmon polaritons at a metal surface structured with a dielectric material to obtain a unique control of their propagation. We exploit this to control plasmonic coupling and demonstrate both theoretically and experimentally cloaking over an unprecedented bandwidth (650-900 nm). Our non-resonant plasmonic metamaterial allows a curved reflector to mimic a flat mirror. Our theoretical predictions are validated by experiments mapping the surface light intensity at the wavelength 800 nm

In Subfertile Couple, Abdominal Fat Loss in Men Is Associated with Improvement of Sperm Quality and Pregnancy: A Case-Series

International audienceBackground: The impact of overweight among men of reproductive-age may affect fertility. Abdominal fat, more than body mass index, is an indicator of higher metabolic risk, which seems to be involved in decreasing sperm quality. This study aims to assess the relationship between abdominal fat and sperm DNA fragmentation and the effect of abdominal fat loss, among 6 men in subfertile couples. Methods: Sperm DNA fragmentation, abdominal fat and metabolic and hormonal profiles were measured in the 6 men before and after dietary advices. Seminal oxidative stress and antioxidant markers were determined. Results: After several months of a lifestyle program, all 6 men lost abdominal fat (patient 1: loss of 3 points of abdominal fat, patient 2: loss of 3 points, patient 3: loss of 2 points, patient 4: loss of 1 point, patient 5: loss of 4 points and patient 6: loss of 13 points). At the same time, their rate of sperm DNA fragmentation decreased: 9.5% vs 31%, 24% vs 43%, 18% vs 47%, 26.3% vs 66%, 25.4% vs 35% and 1.7% vs 25%. Also, an improvement in both metabolic (significant decrease in triglycerides and total cholesterol; p = 0.0139) and hormonal (significant increase in testosterone/oestradiol ratio; p = 0.0139) blood profiles was observed after following the lifestyle program. In seminal plasma, the amount of SOD2 has significantly increased (p = 0.0139) while in parallel carbonylated proteins have decreased. Furthermore, all spouses got pregnant. All pregnancies were brought to term. Conclusion: This study shows specifically that sperm DNA fragmentation among men in subfertile couples could be affected by abdominal fat, but improvement of lifestyle factor may correct this alteration. The effect of specific abdominal fat loss on sperm quality needs further investigation. The reduction of oxidative stress may be a contributing factor

Learning to Segment Dynamic Objects using SLAM Outliers

We present a method to automatically learn to segment dynamic objects using SLAM outliers. It requires only one monocular sequence per dynamic object for training and consists in localizing dynamic objects using SLAM outliers, creating their masks, and using these masks to train a semantic segmentation network. We integrate the trained network in ORB-SLAM 2 and LDSO. At runtime we remove features on dynamic objects, making the SLAM unaffected by them. We also propose a new stereo dataset and new metrics to evaluate SLAM robustness. Our dataset includes consensus inversions, i.e., situations where the SLAM uses more features on dynamic objects that on the static background. Consensus inversions are challenging for SLAM as they may cause major SLAM failures. Our approach performs better than the State-of-the-Art on the TUM RGB-D dataset in monocular mode and on our dataset in both monocular and stereo modes.Comment: Accepted to ICPR 202

Experimental study of the role of trap symmetry in an atom-chip interferometer above the Bose-Einstein condensation threshold

We report the experimental study of an atom-chip interferometer using ultracold rubidium 87 atoms above the Bose-Einstein condensation threshold. The observed dependence of the contrast decay time with temperature and with the degree of symmetry of the traps during the interferometer sequence is in good agreement with theoretical predictions published in [Dupont-Nivet et al., NJP 18, 113012 (2016)]. These results pave the way for precision measurements with trapped thermal atoms.Comment: 11 pages, 4 figure