The detection of ‘virtual’ objects using echoes by humans: Spectral cues

Daniel Rowan*, Timos Papadopoulos, Lauren Archer, Amanda Goodhew, Hayley Cozens, Ricardo Guzman Lopez, David Edwards, Hannah Holmes, Robert Allen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

Some blind people use echoes to detect discrete, silent objects to support their spatial orientation/navigation, independence, safety and wellbeing. The acoustical features that people use for this are not well understood. Listening to changes in spectral shape due to the presence of an object could be important for object detection and avoidance, especially at short range, although it is currently not known whether it is possible with echolocation-related sounds. Bands of noise were convolved with recordings of binaural impulse responses of objects in an anechoic chamber to create ‘virtual objects’, which were analysed and played to sighted and blind listeners inexperienced in echolocation. The sounds were also manipulated to remove cues unrelated to spectral shape. Most listeners could accurately detect hard flat objects using changes in spectral shape. The useful spectral changes for object detection occurred above approximately 3 kHz, as with object localisation. However, energy in the sounds below 3 kHz was required to exploit changes in spectral shape for object detection, whereas energy below 3 kHz impaired object localisation. Further recordings showed that the spectral changes were diminished by room reverberation. While good high-frequency hearing is generally important for echolocation, the optimal echo-generating stimulus will probably depend on the task.

Original languageEnglish
Pages (from-to)205-216
Number of pages12
JournalHearing Research
Volume350
DOIs
Publication statusPublished - 1 Jul 2017
Externally publishedYes

Bibliographical note

Funding Information:
Thanks to Leah Evans for help with measurement of the impulse responses. David Edwards was supported by a RCUK studentship through a Basic Technology Programme grant to the Bio-Inspired Acoustical Systems EP/C523776/1 project (www.biasweb.org). We?are extremely grateful to the Associate Editor, Brian Moore, and two?anonymous reviewers for their critical comments and numerous suggestions, which have improved the paper substantially. Box-plotswere created using a (modified) template produced by?Vertex42 (www.vertex42.com/ExcelTemplates/box-whisker-plot.html). A database of IRs covering a wide range of conditions, including those in the current paper, can be downloaded via: www.southampton.ac.uk/engineering/research/projects/make_like_a_bat.page and 10.5258/SOTON/D0070.

Publisher Copyright:
© 2017 The Authors

Keywords

  • Binaural
  • Blind
  • Echolocation
  • Human
  • Spatial

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