Ventriloquism effect with sound stimuli varying in both azimuth and elevation

Copyright 2015 Acoustical Society of America. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the Acoustical Society of America.The following article appeared in Etienne Hendrickx, Mathieu Paquier, Vincent Koehl and Julian Palacino, Ventriloquism effect with sound stimuli varying in both azimuth and elevation, The Journal of the Acoustical Society of America 2015, vol. 138, no 6, pp. 3686–3697.and may be found at http://link.aip.org/link/?JAS/138/3686International audienceWhen presented with a spatially discordant auditory-visual stimulus, subjects sometimes perceive the sound and the visual stimuli as coming from the same location. Such a phenomenon is often referred to as perceptual fusion or ventriloquism, as it evokes the illusion created by a ventriloquist when his voice seems to emanate from his puppet rather than from his mouth. While this effect has been extensively examined in the horizontal plane and to a lesser extent in distance, few psychoacoustic studies have focused on elevation. In the present experiment, sequences of a man talking were presented to subjects. His voice could be reproduced on different loudspeakers, which created disparities in both azimuth and elevation between the sound and the visual stimuli. For each presentation, subjects had to indicate whether the voice seemed to emanate from the mouth of the actor or not. Results showed that ventriloquism could be observed with larger audiovisual disparities in elevation than in azimuth

Audiovisual Reproduction in Surrounding Display: Effect of Spatial Width of Audio and Video

Moniaistinen havaitseminen perustuu informaation yhdistämiseen eri aistikanavista siten, että yhdistetty aistimus tuottaa enemmän tietoa ympäröivästä maailmasta kuin aistimusten käsitteleminen erillisinä. Tämän seurauksena vanhat laatumittarit yhteen aistiin perustuville järjestelmille eivät toimi arvioitaessa monimutkaisempia audiovisuaalisia järjestelmiä, ja uusien laatumittareiden kehittäminen on tarpeellista. Tässä työssä audiovisuaalista havaitsemista tutkittiin immersiivisen audiovisuaalisen näytön avulla. Näyttö koostui 226 laajasta videokuvasta ja 20 kaiuttimella toteutetusta 3D äänentoistosta. Tutkimuksen tavoite oli tarkkailla kuulon ja näön vuorovaikutusta, kun kuvan- ja äänentoiston avaruudellista laajuutta rajoitettiin. Subjektiivinen laatuarviointi toteutettiin käyttäen diskreettiä näytteenhuonontumaskaalaa (DCR) havaitun laadun heikkenemisen arviointiin neljän eri videosisällön kanssa, kun äänen- ja kuvantoiston leveyttä rajoitettiin. Tämän lisäksi osallistujilta kerättiin vapaita kuvauksia heidän antamiinsa laatuarviointeihin vaikuttaneista seikoista. Osallistujien yksilölliset taipumukset kokea uppoutumista arvioitiin ennen koetta kyselylomakkeen avulla. Tulokset osoittavat, että videon leveys on määräävä tekijä arvioitaessa havaittua laadun heikkenemistä. Myös äänenleveydellä oli merkitystä, kun videonleveys oli suurimmillaan. Taipumus kokea uppoutumista ei ollut merkittävä tekijä laadun kannalta tässä tutkimuksessa. Videosisällön merkitys oli vähäinen. Vapaille kuvauksille suoritettu rajoitettu korrespondenssianalyysi ehdottaa huonoon havaittuun laatuun vaikuttaviksi tekijöiksi äänen väärän tulosuunnan, rajoitetun videonleveyden ja puuttuvan tärkeän sisällön.Multimodal perception strives to integrate information from multiple sensorial channels into a unified experience, that contains more information than just the sum of the separate unimodal percepts. As a result, traditional quality metrics for unimodal services cannot reflect the perceived quality in multimodal situations, and new quality estimation methods are needed. In this work, audiovisual perception was studied with an immersive audiovisual display. The audiovisual display consisted of a video screen with field of view of 226 and 3D sound reproduction with 20 loudspeakers. The aim of the study was to observe the crossmodal interaction of auditory and visual modalities, when the spatial widths of audio and video reproduction were limited. A subjective study was organized, where the overall perceived degradation of the stimuli was evaluated with Degradation Category Rating in four different types of audiovisual content. In addition, free descriptions of the most prominent degrading factors were collected. The participants' individual tendencies to experience immersion were screened prior to the experiment with a questionnaire. The results show that video width is the dominant element in defining the degradation of a stimulus. Also audio width had an impact when the video width was at maximum. Individual tendency to experience immersion was not found to have significant impact on perceived degradation in this study. Slight content effects were observed. Constrained correspondence analysis of the free description data suggests the reasons for highest perceived degradation to be caused by wrong audio direction, reduced video width and missing essential content

Sonic Interactions in Virtual Environments

This open access book tackles the design of 3D spatial interactions in an audio-centered and audio-first perspective, providing the fundamental notions related to the creation and evaluation of immersive sonic experiences. The key elements that enhance the sensation of place in a virtual environment (VE) are: Immersive audio: the computational aspects of the acoustical-space properties of Virutal Reality (VR) technologies Sonic interaction: the human-computer interplay through auditory feedback in VE VR systems: naturally support multimodal integration, impacting different application domains Sonic Interactions in Virtual Environments will feature state-of-the-art research on real-time auralization, sonic interaction design in VR, quality of the experience in multimodal scenarios, and applications. Contributors and editors include interdisciplinary experts from the fields of computer science, engineering, acoustics, psychology, design, humanities, and beyond. Their mission is to shape an emerging new field of study at the intersection of sonic interaction design and immersive media, embracing an archipelago of existing research spread in different audio communities and to increase among the VR communities, researchers, and practitioners, the awareness of the importance of sonic elements when designing immersive environments

Sonic Interactions in Virtual Environments

This open access book tackles the design of 3D spatial interactions in an audio-centered and audio-first perspective, providing the fundamental notions related to the creation and evaluation of immersive sonic experiences. The key elements that enhance the sensation of place in a virtual environment (VE) are: Immersive audio: the computational aspects of the acoustical-space properties of Virutal Reality (VR) technologies Sonic interaction: the human-computer interplay through auditory feedback in VE VR systems: naturally support multimodal integration, impacting different application domains Sonic Interactions in Virtual Environments will feature state-of-the-art research on real-time auralization, sonic interaction design in VR, quality of the experience in multimodal scenarios, and applications. Contributors and editors include interdisciplinary experts from the fields of computer science, engineering, acoustics, psychology, design, humanities, and beyond. Their mission is to shape an emerging new field of study at the intersection of sonic interaction design and immersive media, embracing an archipelago of existing research spread in different audio communities and to increase among the VR communities, researchers, and practitioners, the awareness of the importance of sonic elements when designing immersive environments

Quality-controlled audio-visual depth in stereoscopic 3D media

BACKGROUND: The literature proposes several algorithms that produce “quality-controlled” stereoscopic depth in 3D films by limiting the stereoscopic depth to a defined depth budget. Like stereoscopic displays, spatial sound systems provide the listener with enhanced (auditory) depth cues, and are now commercially available in multiple forms. AIM: We investigate the implications of introducing auditory depth cues to quality-controlled 3D media, by asking: “Is it important to quality-control audio-visual depth by considering audio-visual interactions, when integrating stereoscopic display and spatial sound systems?” MOTIVATION: There are several reports in literature of such “audio-visual interactions”, in which visual and auditory perception influence each other. We seek to answer our research question by investigating whether these audio-visual interactions could extend the depth budget used in quality-controlled 3D media. METHOD/CONCLUSIONS: The related literature is reviewed before presenting four novel experiments that build upon each other’s conclusions. In the first experiment, we show that content created with a stereoscopic depth budget creates measurable positive changes in audiences’ attitude towards 3D films. These changes are repeatable for different locations, displays and content. In the second experiment we calibrate an audio-visual display system and use it to measure the minimum audible depth difference. Our data is used to formulate recommendations for content designers and systems engineers. These recommendations include the design of an auditory depth perception screening test. We then show that an auditory-visual stimulus with a nearer auditory depth is perceived as nearer. We measure the impact of this effect upon a relative depth judgement, and investigate how the impact varies with audio-visual depth separation. Finally, the size of the cross-modal bias in depth is measured, from which we conclude that sound does have the potential to extend the depth budget by a small, but perceivable, amount

Quel son spatialisé pour la vidéo 3D ? : influence d'un rendu Wave Field Synthesis sur l'expérience audio-visuelle 3D

The digital entertainment industry is undergoing a major evolution due to the recent spread of stereoscopic-3D videos. It is now possible to experience 3D by watching movies, playing video games, and so on. In this context, video catches most of the attention but what about the accompanying audio rendering? Today, the most often used sound reproduction technologies are based on lateralization effects (stereophony, 5.1 surround systems). Nevertheless, it is quite natural to wonder about the need of introducing a new audio technology adapted to this new visual dimension: the depth. Many alternative technologies seem to be able to render 3D sound environments (binaural technologies, ambisonics, Wave Field Synthesis). Using these technologies could potentially improve users' quality of experience. It could impact the feeling of realism by adding audio-visual spatial congruence, but also the immersion sensation. In order to validate this hypothesis, a 3D audio-visual rendering system is set-up. The visual rendering provides stereoscopic-3D images and is coupled with a Wave Field Synthesis sound rendering. Three research axes are then studied: 1/ Depth perception using unimodal or bimodal presentations. How the audio-visual system is able to render the depth of visual, sound, and audio-visual objects? The conducted experiments show that Wave Field Synthesis can render virtual sound sources perceived at different distances. Moreover, visual and audio-visual objects can be localized with a higher accuracy in comparison to sound objects. 2/ Crossmodal integration in the depth dimension. How to guarantee the perception of congruence when audio-visual stimuli are spatially misaligned? The extent of the integration window was studied at different visual object distances. In other words, according to the visual stimulus position, we studied where sound objects should be placed to provide the perception of a single unified audio-visual stimulus. 3/ 3D audio-visual quality of experience. What is the contribution of sound depth rendering on the 3D audio-visual quality of experience? We first assessed today's quality of experience using sound systems dedicated to the playback of 5.1 soundtracks (5.1 surround system, headphones, soundbar) in combination with 3D videos. Then, we studied the impact of sound depth rendering using the set-up audio-visual system (3D videos and Wave Field Synthesis).Le monde du divertissement numérique connaît depuis plusieurs années une évolution majeure avec la démocratisation des technologies vidéo 3D. Il est désormais commun de visualiser des vidéos stéréoscopiques sur différents supports : au cinéma, à la télévision, dans les jeux vidéos, etc. L'image 3D a considérablement évolué mais qu'en est-il des technologies de restitution sonore associées ? La plupart du temps, le son qui accompagne la vidéo 3D est basé sur des effets de latéralisation, plus au moins étendus (stéréophonie, systèmes 5.1). Il est pourtant naturel de s'interroger sur le besoin d'introduire des événements sonores en lien avec l'ajout de cette nouvelle dimension visuelle : la profondeur. Plusieurs technologies semblent pouvoir offrir une description sonore 3D de l'espace (technologies binaurales, Ambisonics, Wave Field Synthesis). Le recours à ces technologies pourrait potentiellement améliorer la qualité d'expérience de l'utilisateur, en termes de réalisme tout d'abord grâce à l'amélioration de la cohérence spatiale audio-visuelle, mais aussi en termes de sensation d'immersion. Afin de vérifier cette hypothèse, nous avons mis en place un système de restitution audio-visuelle 3D proposant une présentation visuelle stéréoscopique associée à un rendu sonore spatialisé par Wave Field Synthesis. Trois axes de recherche ont alors été étudiés : 1 / Perception de la distance en présentation unimodale ou bimodale. Dans quelle mesure le système audio-visuel est-il capable de restituer des informations spatiales relatives à la distance, dans le cas d'objets sonores, visuels, ou audio-visuels ? Les expériences menées montrent que la Wave Field Synthesis permet de restituer la distance de sources sonores virtuelles. D'autre part, les objets visuels et audio-visuels sont localisés avec plus de précisions que les objets uniquement sonores. 2 / Intégration multimodale suivant la distance. Comment garantir une perception spatiale audio-visuelle cohérente de stimuli simples ? Nous avons mesuré l'évolution de la fenêtre d'intégration spatiale audio-visuelle suivant la distance, c'est-à-dire les positions des stimuli audio et visuels pour lesquelles la fusion des percepts a lieu. 3 / Qualité d'expérience audio-visuelle 3D. Quel est l'apport du rendu de la profondeur sonore sur la qualité d'expérience audio-visuelle 3D ? Nous avons tout d'abord évalué la qualité d'expérience actuelle, lorsque la présentation de contenus vidéo 3D est associée à une bande son 5.1, diffusée par des systèmes grand public (système 5.1, casque, et barre de son). Nous avons ensuite étudié l'apport du rendu de la profondeur sonore grâce au système audio-visuel proposé (vidéo 3D associée à la Wave Field Synthesis)

Sonic interactions in virtual environments

This book tackles the design of 3D spatial interactions in an audio-centered and audio-first perspective, providing the fundamental notions related to the creation and evaluation of immersive sonic experiences. The key elements that enhance the sensation of place in a virtual environment (VE) are: Immersive audio: the computational aspects of the acoustical-space properties of Virutal Reality (VR) technologies Sonic interaction: the human-computer interplay through auditory feedback in VE VR systems: naturally support multimodal integration, impacting different application domains Sonic Interactions in Virtual Environments will feature state-of-the-art research on real-time auralization, sonic interaction design in VR, quality of the experience in multimodal scenarios, and applications. Contributors and editors include interdisciplinary experts from the fields of computer science, engineering, acoustics, psychology, design, humanities, and beyond. Their mission is to shape an emerging new field of study at the intersection of sonic interaction design and immersive media, embracing an archipelago of existing research spread in different audio communities and to increase among the VR communities, researchers, and practitioners, the awareness of the importance of sonic elements when designing immersive environments