One tone, two ears, three dimensions: A robotic investigation of pinnae movements used by rhinolophid and hipposiderid bats
作者:
V. A. Walker,
H. Peremans,
J. C. T. Hallam,
期刊:
The Journal of the Acoustical Society of America
(AIP Available online 1998)
卷期:
Volume 104,
issue 1
页码: 569-579
ISSN:0001-4966
年代: 1998
DOI:10.1121/1.423256
出版商: Acoustical Society of America
数据来源: AIP
摘要:
Bats, which echolocate using broadband calls, are believed to employ the passive acoustic filtering properties of the head and pinnae to provide spectral cues which encode 3-D target angle. Microchiropteran species whose calls consist of a single, constant frequency harmonic (i.e., some species in the familiesRhinolophidaeandHipposideridae) may create additional acoustic localization cues via vigorous pinna movements. In this work, two types of echolocation cues generated by moving a pair of receivers aboard a model sensor head are investigated. In the first case, it is supposed that a common 3-D echolocation principle employed by all bats is the creation of alternative viewing perspectives, and that constant frequency (CF) echolocators use pinnamovementrather thanmorphologyto alter the acoustic axes of their perceptual systems. Alternatively, it is possible rhinolophids and hipposiderids move their ears to create dynamic cues—in the form of frequency and amplitude modulations—which vary systematically with target elevation. Here the use of binaural and monaural timing cues derived from amplitude modulated echo envelopes are investigated. In this case, pinna mobility provides an echolocator with a mechanism for creating dramatic temporal cues for directional sensing which, unlike interaural timing differences, do not degrade with head size.
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