77 research outputs found

    Recognizing Visual Focus of Attention From Head Pose in Natural Meetings

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    Assessing Scene Structuring in Consumer Videos

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    Ein Neues Verfahren zur Messung der Bakteriziden Fähigkeit des Vollblutes

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    Das oben erwahnte Verfahren hat vor den anderen Methoden besonders die Vorzuge, 1) da&#946; man dadurch zu einem sicheren Resultat gelangen und gleichzeitig auch jedes Datum mit exakten Ziffern zum Ausdruck bringen kann, 2) da&#946; bei diesem Verfahren keineswegs erforderlich ist, eine bestimmte Anzahl von Keimen einschlie&#946;ende Bakterienaufschwemmung herzusteHen und auch Kontrollversuch anzustellen, 3) da&#946; es von den Fehlern des Mischverhaltnisses zwischen der Bakterienlosung und dem Blut nicht so erheblich beeinflu&#946;t wird, und 4) da&#946; man durch dieses Verfahren gleichzeitig mehrere bakterientotende Faktoren untersuchen kann. Ferner hat dieses Verfahren auch den Vorzug, da&#946; es praktisch sehr einfach auszufuhren ist und nur 6 Stunden nach der Blutentnahme bereits das Ergebnis liefert. Es gestattet ferner, die bakterizide Kraft des Blutes gleichzeitig bei 6 - 8 Menschen zu untersuchen, was mich zur Uberzeugung fuhrt, da&#946; es in der Klinik hochgeschatzt werden wird. Auch das Verfahren und die ebenfalls vom mir aufgestellte Formel zur zusammenfassenden Beurteilung kann man nach meinem Erachten durch entsprechende Veranderungen einiger Faktoren ohne jede Schwierigkeiten auch fur andere Bakterienarten anwenden. Man wird wohl gegen eine einzige Lucke dieses Verfahrens, da&#946; die mikroskopische Untersuchung und die Berechnung allzu verwickelt zu sein scheint, Einwand erheben, eine Lucke, zu deren Schlu&#946; jedoch nur eine kurzfristige Ubung erfordert wird, durch welche die mikroskopische Untersuchung innerhalb 30 Minuten, die Berechnung nur in 5 Minuten vollendet werden kann. (Zur Berechnung bedarf es einer Gauss'schen Logarithmentafel.) Obgleich das geschilderte Verfahren noch viele, genauere Prufungen erheischende Punkte in sich einschlie&#946;t, mu&#946; es hier, wenn auch in Grundzugen, jetzt schon angefuhrt werden,. da ich der festen Uberzeugung bin, da&#946; es im Vergleich zu den bisherigen Methoden ein dem wirklichen Wert der Bakterizidie des Vollblutes im lebenden Organismus viel naheres Resultat liefert.</p

    Camera motion estimation through planar deformation determination

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    In this paper, we propose a global method for estimating the motion of a camera which films a static scene. Our approach is direct, fast and robust, and deals with adjacent frames of a sequence. It is based on a quadratic approximation of the deformation between two images, in the case of a scene with constant depth in the camera coordinate system. This condition is very restrictive but we show that provided translation and depth inverse variations are small enough, the error on optical flow involved by the approximation of depths by a constant is small. In this context, we propose a new model of camera motion, that allows to separate the image deformation in a similarity and a ``purely'' projective application, due to change of optical axis direction. This model leads to a quadratic approximation of image deformation that we estimate with an M-estimator; we can immediatly deduce camera motion parameters.Comment: 21 pages, version modifi\'ee accept\'e le 20 mars 200

    Stressful first impressions in job interviews

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    Stress can impact many aspects of our lives, such as the way we interact and work with others, or the first impressions that we make. In the past, stress has been most commonly assessed through self-reported questionnaires; however, advancements in wearable technology have enabled the measurement of physiological symptoms of stress in an unobtrusive manner. Using a dataset of job interviews, we investigate whether first impressions of stress (from annotations) are equivalent to physiological measurements of the electrodermal activity (EDA). We examine the use of automatically extracted nonverbal cues stemming from both the visual and audio modalities, as well EDA stress measurements for the inference of stress impressions obtained from manual annotations. Stress impressions were found to be significantly negatively correlated with hireability ratings i.e individuals who were perceived to be more stressed were more likely to obtained lower hireability scores. The analysis revealed a significant relationship between audio and visual features but low predictability and no significant effects were found for the EDA features. While some nonverbal cues were more clearly related to stress, the physiological cues were less reliable and warrant further investigation into the use of wearable sensors for stress detection

    Tracking Growing Axons by Particle Filtering in 3D+t Fluorescent Two-Photon Microscopy Images

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    International audienceAnalyzing the behavior of axons in the developing nervous systems is essential for biologists to understand the biological mechanisms underlying how growing axons reach their target cells. The analysis of the motion patterns of growing axons requires detecting axonal tips and tracking their trajectories within complex and large data sets. When performed manually, the tracking task is arduous and time-consuming. To this end, we propose a tracking method, based on the particle filtering technique, to follow the traces of axonal tips that appear as small bright spots in the 3D+t fluorescent two-photon microscopy images exhibiting low signal-to-noise ratios (SNR) and complex background. The proposed tracking method uses multiple dynamic models in the proposal distribution to predict the positions of the growing axons. Furthermore, it incorporates object appearance, motion characteristics of the growing axons, and filament information in the computation of the observation model. The integration of these three sources prevents the tracker from being distracted by other objects that have appearances similar to the tracked objects, resulting in improved accuracy of recovered trajectories. The experimental results obtained from the microscopy images show that the proposed method can successfully estimate trajectories of growing axons, demonstrating its effectiveness even under the presence of noise and complex background
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