Jean-Dominique Gascuel

2013

In peer reviewed journal articles

Auteurs

Nicolas Holzschuch ; Jean-Dominique Gascuel

Titre

Double and Multiple-scattering Effects in Translucent Materials

Résumé

Some materials, such as coffee, milk or marble, have a soft translucent aspect because of sub-surface scattering: light enters them, is scattered several times inside before leaving in a different place. A full representation of sub-surface scattering effects in illumination simulation is computationally expensive. The main difficult comes from multiple scattering events: the high number of events increases the uncertainty on the result, forcing us to allocate more time for the computations. In this paper, we show that there is a strong correlation between the surface effects of multiple scattering inside the material and the effects after just two scatter events. This knowledge will help in accelerating multiple scattering effects. We exploit this knowledge to provide a model and implementation for fast computation of double-scattering events, using a precomputed density function stored in a compact way.

Détail

IEEE Computer Graphics and Applications, IEEE, 2013, Special Issue on Scattering: Acquisition, Modeling and rendering, 33 (3)

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2012

In peer reviewed journal articles

Auteurs

Jean-Dominique Gascuel ; Henri Payno; Sébastien Schmerber; Olivier Martin

Titre

Immersive Virtual Environment for Visuo-Vestibular Therapy: Preliminary Results

Résumé

The sense of equilibrium aggregates several interacting cues. On patients with vestibular loss, vision plays a major role. In this study, the goal is to propose a new immersive therapy based on 3D opto-kinetic stimulation. We propose to demonstrate that 3D monoscopic optical flows are an efficient tool to stimulate adaptive postural adjustment. We developed an immersive therapeutic platform that enables to tune the balance task difficulty by managing optic flow speed and gaze anchoring. METHODOLOGY: the immersive sessions proposed to vestibular areflexic patients are composed of a repetition of dynamic optic flows, with varying speed and presence or not of a gaze anchor. The balance adjustments are recorded by a force plate, and quantified by the length of the center of pressure trajectory. RESULTS: Preliminary analysis shows that (i) Patients report a strong immersion felling in the motion flow, triggering more intense motor response to "fight against fall" than in standard opto-kinetic protocols; (ii) An ANOVA factorial design shows a significant effect of flow speed, session number and gaze anchor impact. CONCLUSION: This study shows that 3D immersive stimulation removes essential limits of traditional opto-kinetic stimulators (limited 2D motions and remaining fixed background cues). Moreover, the immersive optic flow stimulation is an efficient tool to induce balance adaptive reactions in vestibular patients. Hence, such a platform appears to be a powerful therapeutic tool for training and relearning of balance control processes.

Détail

Journal of CyberTherapy & Rehabilitation, 2012, 5 (2), p. 127

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Popular scientific articles

Auteurs

Jacques Lemordant; Jean-Dominique Gascuel; Isabelle Bellin

Titre

L'émergence de la réalité augmentée, à la frontière du réel et du virtuel

Résumé

La simulation interactive d'environnements réels ou imaginaires se développe depuis les années 1980. D'abord l'apanage des jeux vidéo, elle est désormais utilisée dans des simulateurs de toutes sortes (camion, super-tanker, train, avion), les visites de sites virtuels (musées, sites archéologiques) ou pour soigner (phobies, troubles de l'équilibre, etc.). Outre les progrès en matière d'images de synthèse, indispensables pour ces applications, c'est la miniaturisation qui a révolutionné les usages.

Détail

Collection "20 ans d'avancées et de perspectives en sciences du numérique" par les chercheurs d'équipes Inria de Grenoble et Lyon., Inria, 2012, 3 p.

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In peer reviewed conference proceedings

Auteurs

Jean-Dominique Gascuel; Henri Payno; Sebastien Schmerber; Olivier Martin

Titre

Immersive Virtual Environment for Visuo-Vestibular Therapy: Preliminary Results

Résumé

The sense of equilibrium aggregates several interacting cues. On patients with vestibular loss, vision plays a major role. In this study, the goal is to propose a new immersive therapy based on 3D opto-kinetic stimulation. We propose to demonstrate that 3D monoscopic optical flows are an efficient tool to stimulate adaptive postural adjustment. We developed an immersive therapeutic platform that enables to tune the balance task difficulty by managing optic flow speed and gaze anchoring. METHODOLOGY: the immersive sessions proposed to vestibular areflexic patients are composed of a repetition of dynamic optic flows, with varying speed and presence or not of a gaze anchor. The balance adjustments are recorded by a force plate, and quantified by the length of the center of pressure trajectory. RESULTS: Preliminary analysis shows that (i) Patients report a strong immersion felling in the motion flow, triggering more intense motor response to "fight against fall" than in standard opto-kinetic protocols; (ii) An ANOVA factorial design shows a significant effect of flow speed, session number and gaze anchor impact. CONCLUSION: This study shows that 3D immersive stimulation removes essential limits of traditional opto-kinetic stimulators (limited 2D motions and remaining fixed background cues). Moreover, the immersive optic flow stimulation is an efficient tool to induce balance adaptive reactions in vestibular patients. Hence, such a platform appears to be a powerful therapeutic tool for training and relearning of balance control processes.

Détail

Brenda K. Wiederhold and Giuseppe Riva. 17th Annual CyberPsychology & CyberTherapy Conference (CYBER17), Sep 2012, Bruxelles, Belgium. IOS Press, Annual Review of Cybertherapy and Telemedicine 2012, 181, pp. 187-191, Studies in Health Technology and Informatics

DOI

DOI : 10.3233/978-1-61499-121-2-187

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2009

In peer reviewed journal articles

Auteurs

Olivier Martin; Jean-Dominique Gascuel

Titre

Reactive Balance Control in Immersive Visual Flows: 2D vs 3D Virtual Stimuli

Résumé

The aim is to study the effects of 2D vs. 3D visual inputs on balance control. Ten subjects were fully immersed in virtual environment, using 10 different 2D/3D motion flow conditions. Analysis of visual and postural responses shows significant differences of reactivity in 3D versus 2D.

Détail

Cyberpsychology and Behavior, 2009, 12 (5), pp. 581-673

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In peer reviewed conference proceedings

Auteurs

Olivier Martin; Jean-Dominique Gascuel

Titre

Reactive Balance Control in Immersive Visual Flows: 2D vs 3D Virtual Stimuli

Résumé

The aim is to study the effects of 2D vs. 3D visual inputs on balance control. Ten subjects were fully immersed in virtual environment, using 10 different 2D/3D motion flow conditions. Analysis of visual and postural responses shows significant differences of reactivity in 3D versus 2D.

Détail

Annual CyberTherapy and CyberPsychology 2009 conference, Jun 2009, Lago Maggiore, Italy.

DOI

DOI : 10.3389/conf.neuro.14.2009.06.061

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