Local Positioning System Using Flickering Infrared LEDs

International audienceA minimalistic optical sensing device for the indoor localization is proposed to estimate the relative position between the sensor and active markers using amplitude modulated infrared light. The innovative insect-based sensor can measure azimuth and elevation angles with respect to two small and cheap active infrared light emitting diodes (LEDs) flickering at two different frequencies. In comparison to a previous lensless visual sensor that we proposed for proximal localization (less than 30 cm), we implemented: (i) a minimalistic sensor in terms of small size (10 cm 3), light weight (6 g) and low power consumption (0.4 W); (ii) an Arduino-compatible demodulator for fast analog signal processing requiring low computational resources; and (iii) an indoor positioning system for a mobile robotic application. Our results confirmed that the proposed sensor was able to estimate the position at a distance of 2 m with an accuracy as small as 2-cm at a sampling frequency of 100 Hz. Our sensor can be also suitable to be implemented in a position feedback loop for indoor robotic applications in GPS-denied environment

Real-time Digital Double Framework to Predict Collapsible Terrains for Legged Robots

Inspired by the digital twinning systems, a novel real-time digital double framework is developed to enhance robot perception of the terrain conditions. Based on the very same physical model and motion control, this work exploits the use of such simulated digital double synchronized with a real robot to capture and extract discrepancy information between the two systems, which provides high dimensional cues in multiple physical quantities to represent differences between the modelled and the real world. Soft, non-rigid terrains cause common failures in legged locomotion, whereby visual perception solely is insufficient in estimating such physical properties of terrains. We used digital double to develop the estimation of the collapsibility, which addressed this issue through physical interactions during dynamic walking. The discrepancy in sensory measurements between the real robot and its digital double are used as input of a learning-based algorithm for terrain collapsibility analysis. Although trained only in simulation, the learned model can perform collapsibility estimation successfully in both simulation and real world. Our evaluation of results showed the generalization to different scenarios and the advantages of the digital double to reliably detect nuances in ground conditions.Comment: IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS). Preprint version. Accepted June 202

Hyperacute artificial compound eye : robotic application to stabilization and pursuit

Inspirés par les propriétés optiques des yeux composés de la mouche et par l’observation de micromouvements périodiques de sa rétine, différents capteurs visuels ont montré qu’il était possible de localiser un contraste très précisément. Ce fut les premières démonstrations d’hyperacuité visuelle de l’œil de la mouche.Dans cette thèse, un œil composé artificiel, doté d'un large champ de vision, est utilisé. Grâce à un nouvel algorithme de fusion des données visuelles, cet œil peut mesurer le déplacement d’un robot et lui permettre de se stabiliser au-dessus d’un environnement texturé. Localiser un contraste de manière linéaire sur l'ensemble du champ visuel demeure toutefois difficile. Un deuxième algorithme permet d’améliorer la localisation d’une barre grâce à un étalonnage, mais montre une certaine dépendance aux variations de contraste et de luminosité ambiante.Afin d'éviter ce processus d’étalonnage, un troisième algorithme qui s’appuie sur les travaux d'Heiligenberg et Baldi, a été proposé pour localiser deux contrastes. Ces auteurs ont montré que la somme pondérée de plusieurs capteurs ayant un champ récepteur gaussien pouvait fournir une estimation linéaire de la position d'un stimulus. Nous avons, pour la première fois, appliqué une variante de ce principe à un œil composé artificiel. Cet œil, une fois monté sur un robot permet de suivre une cible à une distance constante.Finalement, un œil composé artificiel dont la résolution intrinsèque est faible, peut être doté d’une hyperacuité visuelle et permettre de suivre une cible avec précision. Ces travaux ont ainsi conduit à proposer des stratégies bio-inspirées pour la localisation et la poursuite de cible.Inspired by the optical properties of the fly compound eyes and the observation of its retinal periodic micro-movements, several visual sensors established that the localization of a contrast can be made very precisely. It was the first demonstration of the visual hyperacuity of the fly compound eye.In this thesis, an artificial compound eye with a wide field of view was used. Thanks to a novel algorithm fusing the visual signals, the sensor embedded onboard an aerial robot measures its displacement and enables the robot to hover above a textured environment.The localization of a contrast precisely over the whole field of view is still difficult. A second algorithm improved the localization of a bar thanks to a calibration. But it has a dependency to the contrast and the illuminance variations.In order to avoid a calibration process, a third algorithm was proposed to localize two contrasts. It is based on the work of Heiligenberg and Baldi, which showed that an array of Gaussian receptive field can provide a linear estimation of a stimulus position. For the first time, we applied a modified version of their estimation to an artificial compound eye. This sensor mounted on a rover allows following a target precisely at a constant distance.Finally, an artificial compound eye with a coarse spatial resolution can be endowed with hyperacuity and enables a robot to follow a target with precision. A step forward has been made toward bio-inspired target localization and pursuit

Espee: Event-based sensor pose estimation using an extended kalman filter

10.3390/s21237840Sensors2123784

Visual Odometry and Low Optic Flow Measurement by Means of a Vibrating Artificial Compound Eye

4th International Conference on Biomimetic and Biohybrid Systems (Living Machines), Barcelona, SPAIN, JUL 28-31, 2015International audienceIn this study, a tiny artificial compound eye (diameter 15mm) named CurvACE (which stands for Curved Artificial Compound Eye), was endowed with hyperacuity, based on an active visual process inspired by the retinal micro-movements occurring in the fly's compound eye. A periodic (1-D, 50-Hz) micro-scanning movement with a range of a few degrees (5 degrees) enables the active CurvACE to locate contrasting objects with a 40-fold greater accuracy which was restricted by the narrow interommatidial angle of about 4.2 degrees. This local hyperacuity was extended to a large number of adjacent ommatidia in a novel visual processing algorithm, which merges the output signals of the local processing units running in parallel on a tiny, cheap micro-controller requiring very few computational resources. Tests performed in a textured (indoor) or natural (outdoor) environment showed that the active compound eye serves as a contactless angular position sensing device, which is able to assess its angular position relative to the visual environment. As a consequence, the vibrating compound eye is able to measure very low rotational optic flow up to 20 degrees/s and perform a short range odometry knowing the altitude, which are two tasks of great interest for robotic applications

A Bio-inspired Sighted Robot Chases like a Hoverfly

International audienceHere we present a novel bio-inspired visual processing system, which enables a robot to locate and follow a target, using an artificial compound eye called CurvACE. This visual sensor actively scanned the environment at an imposed frequency (50Hz) with an angular scanning amplitude of 4.2 • and succeeded in locating a textured cylindrical target with hyperacuity, i.e. much finer resolution than the coarse inter-receptor angle of the compound eye. Equipped with this small, lightweight visual scanning sensor, a Mecanum-wheeled mobile robot named ACEbot was able to follow a target at a constant distance by localizing the right and left edges of the target. The localization of the target's contrasted edges is based on a bio-inspired summation of Gaussian receptive fields in the visual system. By means of its auto-adaptive pixels, ACEbot consistently achieved similar pursuit performances under various lighting conditions with a high level of repeatability. The robotic pursuit pattern mimics finely the behavior of the male fly Syritta Pipens L. while pursuing the female. The high similarity in the trajectories as well as the biomimicry of the visual system provides strong support for the hypothesis that flies do maintain center the target and constant its subtended angle during smooth pursuit. Moreover, we discuss the fact that such simple strategy can also provide a trajectory compatible with motion camouflage

A small-scale hyperacute compound eye featuring active eye tremor: application to visual stabilization, target tracking, and short-range odometry

International audienceIn this study, a miniature artificial compound eye (15 mm in diameter) called the curved artificial compound eye (CurvACE) was endowed for the first time with hyperacuity, using similar micro-movements to those occurring in the fly's compound eye. A periodic micro-scanning movement of only a few degrees enables the vibrating compound eye to locate contrasting objects with a 40-fold greater resolution than that imposed by the interommatidial angle. In this study, we developed a new algorithm merging the output of 35 local processing units consisting of adjacent pairs of artificial ommatidia. The local measurements performed by each pair are processed in parallel with very few computational resources, which makes it possible to reach a high refresh rate of 500 Hz. An aerial robotic platform with two degrees of freedom equipped with the active CurvACE placed over naturally textured panels was able to assess its linear position accurately with respect to the environment thanks to its efficient gaze stabilization system. The algorithm was found to perform robustly at different light conditions as well as distance variations relative to the ground and featured small closed-loop positioning errors of the robot in the range of 45 mm. In addition, three tasks of interest were performed without having to change the algorithm: short-range odometry, visual stabilization, and tracking contrasting objects (hands) moving over a textured background

Hardware Architecture and Cutting-Edge Assembly Process of a Tiny Curved Compound Eye

International audienceThe demand for bendable sensors increases constantly in the challenging field of soft and micro-scale robotics. We present here, in more detail, the flexible, functional, insect-inspired curved artificial compound eye (CurvACE) that was previously introduced in the Proceedings of the National Academy of Sciences (PNAS, 2013). This cylindrically-bent sensor with a large panoramic field-of-view of 180 degrees x 60 degrees composed of 630 artificial ommatidia weighs only 1.75 g, is extremely compact and power-lean (0.9 W), while it achieves unique visual motion sensing performance (1950 frames per second) in a five-decade range of illuminance. In particular, this paper details the innovative Very Large Scale Integration (VLSI) sensing layout, the accurate assembly fabrication process, the innovative, new fast read-out interface, as well as the auto-adaptive dynamic response of the CurvACE sensor. Starting from photodetectors and microoptics on wafer substrates and flexible printed circuit board, the complete assembly of CurvACE was performed in a planar configuration, ensuring high alignment accuracy and compatibility with state-of-the art assembling processes. The characteristics of the photodetector of one artificial ommatidium have been assessed in terms of their dynamic response to light steps. We also characterized the local auto-adaptability of CurvACE photodetectors in response to large illuminance changes: this feature will certainly be of great interest for future applications in real indoor and outdoor environments

Avis relatif à l’actualisation des recommandations sanitaires concernant le port du masque dans les structures d’accueil des enfants âgés de 0 à 3 ans (HCSP, Avis et Rapports)

International audienceAvis relatif à l’actualisation des recommandations sanitaires concernant le port du masque dans les structures d’accueil des enfants âgés de 0 à 3 ans (HCSP, Avis et Rapports)Christian CHIDIAC, Philippe MINODIER, Nicole VERNAZZA, Yannick AUJARD, Didier LEPELLETIER, Jean-Marc BRIGNON, Philippe HARTEMANN, Yves LEVI, Francelyne MARANO, Fabien SQUINAZI, Agathe BILLETTE de VILLEMEUR, Anne BERGER-CARBONNE, Nicolas ETERRADOSSI, Gilles SALVAT, Brigitte MOLTRECHT, Éric GAFFET, Camille BRUAT, Annette COLONNIERVersion du 09 septembre 2020Date de mise en ligne : 17/09/2020https://www.hcsp.fr/Explore.cgi/AvisRapportsDomaine?clefr=910CHIDIAC, Christian ; MINODIER, Philippe ; VERNAZZA, Nicole ; AUJARD, Yannick ; LEPELLETIER, Didier ; BRIGNON, Jean-Marc ; HARTEMANN, Philippe ; LEVI, Yves ; MARANO, Francelyne ; SQUINAZI, Fabien ; BILLETTE de VILLEMEUR, Agathe ; BERGER-CARBONNE, Anne ; ETERRADOSSI, Nicolas ; SALVAT, Gilles ; MOLTRECHT, Brigitte ; GAFFET, Éric ; BRUAT, Camille ; COLONNIER, AnnetteCovid-19 : recommandations sanitaires concernant le port du masque dans les établissements accueillant des jeunes enfantsLe HCSP revoit ses recommandations pour le port du masque par les professionnels de l’enfance accueillant les jeunes enfants de 0 à 3 ans en crèches collectives, à domicile par assistante maternelle et en établissement relevant de l’aide sociale à l’enfance.Il tient compte de l’évolution des connaissances sur la transmission du Covid-19 chez les enfants, des recommandations dans d’autres pays et de la perception du risque de transmission par des pédiatres et des responsables de PMI.Il propose deux stratégies de prévention adaptant les différentes mesures (hygiène, aération des locaux, etc.) en fonction du niveau de circulation du virus.En complément de ces différentes mesures, il précise les circonstances du port du masque par les adultes dans le cadre l’accueil des enfants âgés de 0 à 3 ans, en fonction du mode de garde (collectif ou assistante maternelle), du niveau de circulation du virus (active ou sous contrôle) et de l’état de santé des enfants (présence de troubles du comportement, relationnels ou de handicaps). Des masques à fenêtre transparente, tels que ceux validés par la Direction générale de l’armement, sont à privilégier pour les interactions avec certains enfants.Le port du masque n’est pas recommandé chez les jeunes enfants.Lire aussi :Coronavirus SARS-CoV-2 : mesures à mettre en œuvre dans les établissements accueillant des jeunes enfants du 30 avril 2020Covid-19 : adaptation des mesures barrières pour les établissements accueillant des jeunes enfants du 10 juin 2020Covid-19 : doctrines à appliquer dans les milieux scolaire et universitaire et pour l’accueil collectif des mineurs pour la rentrée de septembre 2020 du 7 juillet 2020SARS-CoV-2 : actualisation des connaissances sur la transmission du virus par aérosols du 23 juillet 2020Ministère des solidarités et de la santé : information aux professionnels de sant