Auditory-visual virtual environment for the treatment of fear of crowds

ABSTRACT Fear of crowds is a symptom found in agoraphobia (among others) and which has both visual and auditory relevant components. In order to examine the potential interest of auditory-visual virtual reality to treat fear of crowds, we investigated the efficiency of an auditory-visual virtual environment in evoking affective reaction. We conducted an evaluation test with healthy participants sensitive to the fear of crowds to explore the influence of auditory-visual virtual environment on affective reactions. Our application involves both high fidelity visual stimulation and interactive 3D sound. Our specific presentation of animated crowds of humans creates an environment that is highly arousing, suggesting that manipulating the sensory presentation together with the spatial location of stimulation might provide a way to modulate affective reactions

Retour d'expérience sur les bassins d'orage en réseau unitaire: une solution pour limiter les rejets de temps de pluie

International audienceLe développement des systèmes d'assainissement s'appuie souvent sur des structures construites il y a plusieurs décennies. Ces systèmes font face à une augmentation des niveaux d'exigence qui leur sont assignés. Dans le viseur de l'arrêté de 2015 notamment, les performances par temps de pluie des systèmes de collecte. Un retour d'expériences sur les bassins d'orage mené par le Cerema fait le point sur les interrogations et les solutions trouvées par les gestionnaires. CONTEXTE DE L'ETUDE En collaboration avec l'AFB, le GEMCEA, le Ministère de la transition écologique et solidaire et les Agences de l'eau, le Cerema a réalisé un vaste retour d'expériences sur les bassins d'orage implantés sur les réseaux d'assainissement unitaires. L'objet de ce retour d'expériences était de voir, sur le terrain, comment les gestionnaires/exploitants avaient eu recours à cette technique pour optimiser le fonctionnement de leur système, notamment par temps de pluie, et de collecter des informations techniques et financières quant au fonctionnement, à la conception, au dimensionnement de ce type d'ouvrages. A travers une recherche bibliographique et de nombreux entretiens réalisés auprès de 17 maîtres d'ouvrage/exploitants, ce travail a aussi permis indirectement de recueillir les témoignages des personnes interrogées quant aux enjeux et aux problématiques auxquelles les services peuvent être confrontés, aux difficultés techniques rencontrées, souvent liées à leur contexte local, et à la façon dont les collectivités ont cherché à y remédier notamment par la construction de bassins d'orage. Le projet ayant débuté au 2nd semestre 2013 et s'étant terminé en 2018, nous avons ainsi pu être les témoins, un peu malgré nous, des interrogations des différents acteurs vis-à-vis des évolutions de la réglementation en matière d'assainissement : autosurveillance, diagnostic permanent, choix du critère de conformité du système de collecte, … ainsi que des conséquences des lois NOTRe 5 et MAPTAM 6 sur la répartition des compétences à court et moyen termes. Cette communication fait volontairement le choix de se focaliser sur les éléments recueillis qui concernent les enjeux et opportunités de l'autosurveillance et du diagnostic permanent, les démarches mises en place par les gestionnaires pour optimiser le fonctionnement de leur système et répondre aux nouveaux critères de conformité fixés par l'arrêté de 2015

Effect of Harmonicity on the Detection of a Signal in a Complex Masker and on Spatial Release from Masking

The amount of masking of sounds from one source (signals) by sounds from a competing source (maskers) heavily depends on the sound characteristics of the masker and the signal and on their relative spatial location. Numerous studies investigated the ability to detect a signal in a speech or a noise masker or the effect of spatial separation of signal and masker on the amount of masking, but there is a lack of studies investigating the combined effects of many cues on the masking as is typical for natural listening situations. The current study using free-field listening systematically evaluates the combined effects of harmonicity and inharmonicity cues in multi-tone maskers and cues resulting from spatial separation of target signal and masker on the detection of a pure tone in a multi-tone or a noise masker. A linear binaural processing model was implemented to predict the masked thresholds in order to estimate whether the observed thresholds can be accounted for by energetic masking in the auditory periphery or whether other effects are involved. Thresholds were determined for combinations of two target frequencies (1 and 8 kHz), two spatial configurations (masker and target either co-located or spatially separated by 90 degrees azimuth), and five different masker types (four complex multi-tone stimuli, one noise masker). A spatial separation of target and masker resulted in a release from masking for all masker types. The amount of masking significantly depended on the masker type and frequency range. The various harmonic and inharmonic relations between target and masker or between components of the masker resulted in a complex pattern of increased or decreased masked thresholds in comparison to the predicted energetic masking. The results indicate that harmonicity cues affect the detectability of a tonal target in a complex masker

UNE CAMPAGNE DE MESURES OBJECTIVES ET PERCEPTIVES EN ACOUSTIQUE DES SALLES

Cet article est consacré à la description d'une campagne de mesures et d'écoutes dans le domaine de l'acoustique des salles. Le but de ce travail est d'une part de valider un environnement informatique de modélisation acoustique développé à l'IRCAM et d'autre part de préciser les connaissances sur la perception de la qualité acoustique des salles. L'article décrit les principes qui ont présidé à l'élaboration de cette base de données.This paper describes the organization of a data base in the field of room acoustics. This data base consists of objective measurements recorded in various concert halls together with perceptive judgments collected in the same halls during concerts. The aim is to validate a computer environnement dedicated to room acoustics prediction that was developped at IRCAM and to improve our knowledge on perceptual aspects linked to the acoustical quality of a room

ÉTUDE DES PARAMÈTRES LIÉS À LA PRISE DE SON POUR LES APPLICATIONS D'ACOUSTIQUE VIRTUELLE

Cette étude tente d'évaluer l'influence des paramètres de prise et de restitution du son sur la qualité acoustique perçue par l'auditeur. Suite aux travaux entrepris à l'IRCAM, dans le domaine de la caractérisation en acoustique des salles, cette qualité est analysée sur la base de critères objectifs dont on connaît l'interprétation perceptive. Ces analyses sont effectuées à partir d'une base de donnée élaborée par des simulations informatiques.This paper studies how the parameters of an electroacoustical system will interfer with the acoustical quality perceived by a listener. According to previous studies proceeded at IRCAM on room acoustics characterisation, this quality is analysed with objective criteria which relevancies in perceptive domain have been validated. This study uses data collected through computer simulations

A study of the influence of room acoustics on piano performance

This study attempts to describe the behaviour of a pianist playing the same piece of music in different acoustics. An experiment was organized in march 1993 using carefully controlled experimental conditions. In the variable acoustics of the "Espace de Projection" at Ircam (Paris), seven professional pianists playing on a Disklavier MIDI grand piano were recorded with synchronous digital audio and midi systems. From these data a statistical analysis was performed in order to evaluate to what extent performance attributes are correlated to the perceptual dimensions of room acoustics. The strategy of experimentation, the acoustical realization, the measurements and the methodology of the statistical analysis are described

Environnement de simulation pour l'évaluation psychoacoustique des systèmes de prise et de restitution du son dans un contexte de téléconférence

A simulation environment is used for the perceptual evaluation of sound pickup and reproduction techniques in a teleconference context. A project, named "Spatialisateur", developed by Ircam and Espaces Nouveaux aims at synthesizing virtual room effects, controlling the acoustical quality and the localization aspects in real time. The prototype generates a localization effect by use of binaural reproduction techniques, for a single listener with headphones or a loudspeaker pair. Binaural synthesis relies on the use of head-related transfer functions (HRTF), which realize a listener-specific encoding of localization cues for any position of the sound source. Parametric modelling techniques are used in order to reduce the computational cost of the binaural filtering process. Psychoacoustical tests have been undertaken to validate this prototype by comparing, for various configurations, the localization judgements of subjects in actual stereophonic listening and in headphone simulation of the stereophonic reproduction

Judging crowds' size by ear and by eye in virtual reality

International audienceJudging the size of a group of people is an everyday task, on which many decisions are based. In the present study, we investigated whether judgment of size of different groups of people depended on whether they were presented through the auditory channel, through the visual channel, or through both auditory and visual channels. Groups of humanoids of different sizes (from 8 to 128) were presented within a virtual environment to healthy participants. They had to judge whether there was a lot of people in each group and rate their discomfort in relation to the stimuli with Subjective Units of Distress. Our groups of 96 and 128 virtual humans were judged as crowds regardless of their sensory presentation. The sensory presentation influenced participants’ judgment of virtual human group size ranging from 8 to 48. Moreover, while the quantity judgments in the auditory condition increased linearly with the group size, participants judged the quantity of people in a logarithmic manner in the two other sensory conditions. These results suggest that quantity judgment based on auditory information in a realistic context may often involve implicit arithmetic. Even though our participants were not phobic of crowds, our findings are of interest for the field of virtual reality-based therapy for diverse disorders because they indicate that quantity judgment can potentially be altered in a sensory-specific manner in patients with fear of crowds

Multisensory aversive stimuli differentially modulate negative feelings in near and far space

International audienceAffect, space and multisensory integration are processes that are closely linked. However, it is unclear whether the spatial location of emotional stimuli interacts with multisensory presentation to influence the emotional experience they induce in the perceiver.In this study, we used the unique advantages of virtual reality techniques to present potentially aversive crowd stimuli embedded in a natural context and to control their display in terms of sensory and spatial presentation. Individuals high in crowdphobic fear navigated in an auditory-visual virtual environment, in which they encountered virtual crowds presented through the visual channel, the auditory channel or both. They reported the intensity of their negative emotional experience at a far distance and at a close distance from the crowd stimuli. Whereas auditory-visual presentation of close feared stimuli amplified negative feelings, auditory-visual presentation of distant feared stimuli did not amplify negative feelings.This suggests that spatial closeness allows multisensory processes to modulate the intensity of the emotional experience induced by aversive stimuli. Nevertheless, the specific role of auditory stimulation must be investigated in order to better understand this interaction between multisensory, affective and spatial representation processes. This phenomenon may serve the implementation of defensive behaviors in response to aversive stimuli that are in position to threaten an individual’s feeling of security