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Vibrations de plaques multi-excitateurs de grandes dimensions pour la création d'environnements virtuels audio-visuels: approches acoustique, mécanique et perceptive.

Abstract : Virtual reality provides a transparent window open into a virtual world in which users are immersed. Initially being primarily visual, these virtual worlds now also include sound, thanks to recently developed spatialized sound rendering technologies. A new system proposed and studied here is comprised of large sandwich panels, used as screens, on the back of which electro-dynamic exciters are attached, thus allowing for the creation of an acoustic field surrounding the users. The 3D visual rendering is generated using tracked passive stereoscopy and the spatial sound rendering is achieved by means of holophony, also known as wave-field synthesis. Using a sandwich panel for holophony supposes that its vibroacoustic behavior is well known. The estimation of non-linearities in vibrating systems is addressed on the basis of an empirical method proposed by A. Farina in 2000. The theoretical basis of the method is justified and extended to allow also for the separation of the contributions of different non-linear components in the measurement chain. A method for the estimation of elastic and damping factors, those that are relevant to the propagation of flexural and shear waves in the sandwich panel, has also been developed. Thanks to these two tools, the system under study has been experimentally characterized. Spatial perception of the virtual world synthesized by the system, using solely audio, visual, or both modalities is then studied. It is shown that participants successfully merge the presented audio and visual streams into a single fused object. Specifically, the audio and visual rendering are perceived as spatially coherent. The characteristics of spatial perception of the virtual world are analyzed with respect to the rendering modalities and results are compared with previous studies. The concept of anchorage of the virtual world to the real world is furthermore proposed: the physical distance between the user and the system affects the perceived degree of distance compression for both modalities. Finally, two virtual reality applications illustrate some of the numerous possibilities offered by this new "computer/human interface".
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https://pastel.archives-ouvertes.fr/pastel-00657634
Contributor : Marc Rébillat <>
Submitted on : Saturday, January 7, 2012 - 7:19:33 PM
Last modification on : Wednesday, October 14, 2020 - 4:02:30 AM
Long-term archiving on: : Sunday, April 8, 2012 - 2:21:32 AM

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  • HAL Id : pastel-00657634, version 1

Citation

Marc Rébillat. Vibrations de plaques multi-excitateurs de grandes dimensions pour la création d'environnements virtuels audio-visuels: approches acoustique, mécanique et perceptive.. Acoustique [physics.class-ph]. Ecole Polytechnique X, 2011. Français. ⟨pastel-00657634⟩

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