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Reaching nearby sources: comparison between real and virtual sound and visual targets.

Parseihian G, Jouffrais C, Katz BF - Front Neurosci (2014)

Bottom Line: The current study concerns localization and pointing accuracy by examining source positions in the peripersonal space, specifically those associated with a typical tabletop surface.Results show no effect on the reporting hand with azimuthal errors increasing equally for the most extreme source positions.Various potential reasons for this discrepancy are discussed with several proposals for improving distance perception in peripersonal virtual environments.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Mécanique et d'Informatique pour les Sciences de l'Ingénieur, LIMSI - CNRS, Universite Paris Sud Orsay, France.

ABSTRACT
Sound localization studies over the past century have predominantly been concerned with directional accuracy for far-field sources. Few studies have examined the condition of near-field sources and distance perception. The current study concerns localization and pointing accuracy by examining source positions in the peripersonal space, specifically those associated with a typical tabletop surface. Accuracy is studied with respect to the reporting hand (dominant or secondary) for auditory sources. Results show no effect on the reporting hand with azimuthal errors increasing equally for the most extreme source positions. Distance errors show a consistent compression toward the center of the reporting area. A second evaluation is carried out comparing auditory and visual stimuli to examine any bias in reporting protocol or biomechanical difficulties. No common bias error was observed between auditory and visual stimuli indicating that reporting errors were not due to biomechanical limitations in the pointing task. A final evaluation compares real auditory sources and anechoic condition virtual sources created using binaural rendering. Results showed increased azimuthal errors, with virtual source positions being consistently overestimated to more lateral positions, while no significant distance perception was observed, indicating a deficiency in the binaural rendering condition relative to the real stimuli situation. Various potential reasons for this discrepancy are discussed with several proposals for improving distance perception in peripersonal virtual environments.

No MeSH data available.


Related in: MedlinePlus

(A) (Color on-line) Mean of all subjects' reported location with 50% confidence ellipse linked to source location for the dominant hand condition. Front/back confusion corrected. Good directional pointing accuracy in the median plane, larger compression of reported distances in front than in side. (B) Mean of all subjects' reported azimuth as a function of the target azimuth for both hand conditions. Error bars show one standard deviation across the subjects. Gray line shows unity. For the sake of readability, results corresponding to the different hand conditions have been slightly horizontally shifted. This plot shows a good pointing accuracy on the frontal hemisphere and lower accuracy on the side. (C) Mean of all subjects' reported distance as a function of target distance with mean of linear regression slope for 1st and 2nd hand across all azimuths. Gray line shows unity. Error bars show one standard deviation across the subjects. Reported distance is linear but compressed.
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Figure 2: (A) (Color on-line) Mean of all subjects' reported location with 50% confidence ellipse linked to source location for the dominant hand condition. Front/back confusion corrected. Good directional pointing accuracy in the median plane, larger compression of reported distances in front than in side. (B) Mean of all subjects' reported azimuth as a function of the target azimuth for both hand conditions. Error bars show one standard deviation across the subjects. Gray line shows unity. For the sake of readability, results corresponding to the different hand conditions have been slightly horizontally shifted. This plot shows a good pointing accuracy on the frontal hemisphere and lower accuracy on the side. (C) Mean of all subjects' reported distance as a function of target distance with mean of linear regression slope for 1st and 2nd hand across all azimuths. Gray line shows unity. Error bars show one standard deviation across the subjects. Reported distance is linear but compressed.

Mentions: Figure 2A presents the mean pointed position (with corrected azimuth) for the 1st and 2nd hand condition with the precision estimated by the 50% confidence ellipse linked to each position. For each target, 50% confidence ellipses were computed across all the subjects and all the conditions according to the method proposed by Murdoch and Chow (1996). The angle of the ellipse is determined by the covariance of the data and the magnitudes of the ellipse axes depend on the variance of the data. These plots highlight a compression of the reported distance dependent on the stimuli angle and a shift of the reported azimuth dependent on the stimuli angle and distance. For example, the azimuth error at 90° is larger for nearer sources and distance perception appears better at lateral angles. Azimuth and distance errors have been analyzed as a function of reporting hand, stimuli azimuth, and stimuli distance.


Reaching nearby sources: comparison between real and virtual sound and visual targets.

Parseihian G, Jouffrais C, Katz BF - Front Neurosci (2014)

(A) (Color on-line) Mean of all subjects' reported location with 50% confidence ellipse linked to source location for the dominant hand condition. Front/back confusion corrected. Good directional pointing accuracy in the median plane, larger compression of reported distances in front than in side. (B) Mean of all subjects' reported azimuth as a function of the target azimuth for both hand conditions. Error bars show one standard deviation across the subjects. Gray line shows unity. For the sake of readability, results corresponding to the different hand conditions have been slightly horizontally shifted. This plot shows a good pointing accuracy on the frontal hemisphere and lower accuracy on the side. (C) Mean of all subjects' reported distance as a function of target distance with mean of linear regression slope for 1st and 2nd hand across all azimuths. Gray line shows unity. Error bars show one standard deviation across the subjects. Reported distance is linear but compressed.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4151089&req=5

Figure 2: (A) (Color on-line) Mean of all subjects' reported location with 50% confidence ellipse linked to source location for the dominant hand condition. Front/back confusion corrected. Good directional pointing accuracy in the median plane, larger compression of reported distances in front than in side. (B) Mean of all subjects' reported azimuth as a function of the target azimuth for both hand conditions. Error bars show one standard deviation across the subjects. Gray line shows unity. For the sake of readability, results corresponding to the different hand conditions have been slightly horizontally shifted. This plot shows a good pointing accuracy on the frontal hemisphere and lower accuracy on the side. (C) Mean of all subjects' reported distance as a function of target distance with mean of linear regression slope for 1st and 2nd hand across all azimuths. Gray line shows unity. Error bars show one standard deviation across the subjects. Reported distance is linear but compressed.
Mentions: Figure 2A presents the mean pointed position (with corrected azimuth) for the 1st and 2nd hand condition with the precision estimated by the 50% confidence ellipse linked to each position. For each target, 50% confidence ellipses were computed across all the subjects and all the conditions according to the method proposed by Murdoch and Chow (1996). The angle of the ellipse is determined by the covariance of the data and the magnitudes of the ellipse axes depend on the variance of the data. These plots highlight a compression of the reported distance dependent on the stimuli angle and a shift of the reported azimuth dependent on the stimuli angle and distance. For example, the azimuth error at 90° is larger for nearer sources and distance perception appears better at lateral angles. Azimuth and distance errors have been analyzed as a function of reporting hand, stimuli azimuth, and stimuli distance.

Bottom Line: The current study concerns localization and pointing accuracy by examining source positions in the peripersonal space, specifically those associated with a typical tabletop surface.Results show no effect on the reporting hand with azimuthal errors increasing equally for the most extreme source positions.Various potential reasons for this discrepancy are discussed with several proposals for improving distance perception in peripersonal virtual environments.

View Article: PubMed Central - PubMed

Affiliation: Laboratoire de Mécanique et d'Informatique pour les Sciences de l'Ingénieur, LIMSI - CNRS, Universite Paris Sud Orsay, France.

ABSTRACT
Sound localization studies over the past century have predominantly been concerned with directional accuracy for far-field sources. Few studies have examined the condition of near-field sources and distance perception. The current study concerns localization and pointing accuracy by examining source positions in the peripersonal space, specifically those associated with a typical tabletop surface. Accuracy is studied with respect to the reporting hand (dominant or secondary) for auditory sources. Results show no effect on the reporting hand with azimuthal errors increasing equally for the most extreme source positions. Distance errors show a consistent compression toward the center of the reporting area. A second evaluation is carried out comparing auditory and visual stimuli to examine any bias in reporting protocol or biomechanical difficulties. No common bias error was observed between auditory and visual stimuli indicating that reporting errors were not due to biomechanical limitations in the pointing task. A final evaluation compares real auditory sources and anechoic condition virtual sources created using binaural rendering. Results showed increased azimuthal errors, with virtual source positions being consistently overestimated to more lateral positions, while no significant distance perception was observed, indicating a deficiency in the binaural rendering condition relative to the real stimuli situation. Various potential reasons for this discrepancy are discussed with several proposals for improving distance perception in peripersonal virtual environments.

No MeSH data available.


Related in: MedlinePlus