Physics-based control of virtual characters in low frequency simulations

International audienceUsing a lower simulation frequency for physics-based control of virtual characters frees computation time that can be used for more complex environment. However, using low simulation frequency may introduce instabilities inside the simulation. In this paper, we demonstrate that even a simple control strategy can be used at a low simulation frequency by adapting the control parameters. Indeed we show that lower frequencies hold a more restrictive space of possible control parameters than higher ones. We propose a method to find optimized control parameters for frequencies as low as 200Hz. As using such low frequencies may introduce foot-ground contact instabilities, we also introduce an additional control feedback on the stance leg. Our controller shows similar robustness as high frequency controller while using 0.8ms per simulation step

Learning-based pose edition for efficient and interactive design

Authoring an appealing animation for a virtual character is a challenging task. In computer-aided keyframe animation artists define the key poses of a character by manipulating its underlying skeletons. To look plausible, a character pose must respect many ill-defined constraints, and so the resulting realism greatly depends on the animator's skill and knowledge. Animation software provide tools to help in this matter, relying on various algorithms to automatically enforce some of these constraints. The increasing availability of motion capture data has raised interest in data-driven approaches to pose design, with the potential of shifting more of the task of assessing realism from the artist to the computer, and to provide easier access to nonexperts. In this article, we propose such a method, relying on neural networks to automatically learn the constraints from the data. We describe an efficient tool for pose design, allowing na{\"i}ve users to intuitively manipulate a pose to create character animations

Exploring human visual system: study to aid the development of automatic facial expression recognition framework

International audienceThis paper focus on understanding human visual system when it decodes or recognizes facial expressions. Results presented can be exploited by the computer vision research community for the development of robust descriptor based on human visual system for facial expressions recognition. We have conducted psycho-visual experimental study to find which facial region is perceptually more attractive or salient for a particular expression. Eye movements of 15 observers were recorded with an eye-tracker in free viewing conditions as they watch a collection of 54 videos selected from Cohn-Kanade facial expression database, showing six universal facial expressions. The results of the study shows that for some facial expressions only one facial region is perceptually more attractive than others. Other cases shows the attractiveness of two to three facial regions. This paper also proposes a novel framework for automatic recognition of expressions which is based on psycho-visual study

Facial Expression Recognition using Entropy and Brightness Features

International audienceThis paper proposes a novel framework for universal facial expression recognition. The framework is based on two sets of features extracted from the face image: entropy and brightness. First, saliency maps are obtained by state-of-the-art saliency detection algorithm i.e. "frequencytuned salient region detection". Then only localized salient facial regions from saliency maps are processed to extract entropy and brightness features. To validate the performance of saliency detection algorithm against human visual system, we have performed a visual experiment. Eye movements of 15 subjects were recorded with an eye-tracker in free viewing conditions as they watch a collection of 54 videos selected from Cohn-Kanade facial expression database. Results of the visual experiment provided the evidence that obtained saliency maps conforms well with human fixations data. Finally, evidence of the proposed framework's performance is exhibited through satisfactory classification results on Cohn-Kanade database

Framework for reliable, real-time facial expression recognition for low resolution images

International audienceAutomatic recognition of facial expressions is a challenging problem specially for low spatial resolution facial images. It has many potential applications in human-computer interactions, social robots, deceit detection, interactive video and behavior monitoring. In this study we present a novel framework that can recognize facial expressions very efficiently and with high accuracy even for very low resolution facial images. The proposed framework is memory and time efficient as it extracts texture features in a pyramidal fashion only from the perceptual salient regions of the face. We tested the framework on different databases, which includes Cohn-Kanade (CK+) posed facial expression database, spontaneous expressions of MMI facial expression database and FG-NET facial expressions and emotions database (FEED) and obtained very good results. Moreover, our proposed framework exceeds state-of-the-art methods for expression recognition on low resolution images

Le projet CIRDO d'assistance aux personnes âgées isolées à domicile

National audienceCIRDO RI est un projet qui vise à mettre au point un système d'assistance pour faciliter le maintien à domicile des personnes âgées et/ou dépendantes. Il a pour objectif de sécuriser les seniors et de favoriser leur autonomie pour soulager les familles et les aidants. L'idée principale du projet CIRDO est d'utiliser à la fois l'analyse vidéo et la reconnaissance de la parole et ceci dans le même processus. Afin de répondre aux contraintes fixées dans le projet CIRDO comme le respect de l'intimité, la préservation de l'information privée et la réactivité dans la détection de situations de détresse, les solutions proposées sont conçues pour opérer en tâches de fond, sans l'intervention d'un opérateur. Outre l'aspect technique, ce projet porte également sur l'évaluation psycho-sociale et psycho-ergonomique de ces technologies par des utilisateurs potentiels et leur entourage (famille, aidants...) au niveau de leur utilisabilité et de leur acceptabilité notamment. Des expérimentations conduites dans un milieu réaliste ont permis l'enregistrement de données audio et vidéo correspondant au cas d'usage

CIRDO: Smart companion for helping elderly to live at home for longer

8 pagesInternational audienceCirdo project is intended to establish new healthcare systems to ensure the safety at home of seniors and people with decreasing independence. In particular, extending "e-lio" (http://www.technosens.fr/) device, Cirdo aims to develop an audio/video-based system which makes it possible for elderly to live with a sufficient degree of autonomy. To achieve this goal, generic purposes on video analysis and audio processing are discussed and implemented in the same process. Audio and video analysis algorithms are launched simultaneously and thinks to GPU implementation, the tasks are done in real time. To comply with the requirements set out in the Cirdo project namely: respect privacy and preserve personal data, the processing tasks is performed through background tasks, without any human intrusion. In order to have different types of fall for our experiences, multiple scenarios were designed and performed by several persons. Besides the technical aspect, the project also focuses on generic technology validation by potential users and their human environment (family, caregivers/care takers...). Psychological and ergonomic assessment on the use of services developed was conducted. It focused on the usefulness, usability and accessibility and acceptance of the tool. This evaluation was completed by critical investigation of knowledge acquired by professionals (geriatricians, caregivers school and associations)

ZF Model Efficiency for Automatic Hand Detection in Vehicles

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A Novel Application of Media Technology : CYBERII Incrustation in a Virtual World of Financial Indicators

International audienceRôle de la réalité augmentée dans le secteur de la financ