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Re: granular synthesis and auditory segmentation

Peter Cariani writes:

>In the correlational view, having all of those
>tuned filters makes the system much more robust
>in the face of background noise [...] The tuning of the
>filters confers upon the system the ability to detect and
>isolate faint auditory objects in the face of competing sounds
>by ensuring that no one sound completely dominates the time
>structure of the auditory nerve array output.

I'll be defending a very similar point of view at the ATR Workshop on
Events and Auditory Temporal Structure.  The paper can be downloaded from:

The abstract is below.


The auditory system as a separation machine

This paper is written from the hypothetical standpoint that the
auditory system is designed to {\em separate}\ sounds rather than just
detect, discriminate, or recognize them.  Auditory structures and
processing mechanisms are judged on their ability to produce a
"separable representation" in which correlates of different sources
can be selected or ignored.  The cochlear filter is assumed to split
acoustic information into band-limited channels, rather than just
produce a spectral representation (Fourier transformation).  Tonotopy,
prevalent throughout the auditory system, is assumed to reflect the
need to keep the channels apart, rather than the mere repetition of a
spectral representation.  Between-channel segregation is supplemented
by within-channel segregation based on time-domain processing, both
binaural (cross-correlation and equalization-cancellation), and
monaural (autocorrelation and harmonic cancellation).  Binaural
processing accounts for binaural unmasking and certain binaural pitch
effects.  Monaural processing accounts for F0-driven segregation, and
pitch and timbre perception.  An essential ingredient in this
hypothesis is "missing-feature theory", that deals with the incomplete
patterns produced by the segregation mechanisms.  Parts of a pattern
are weighted according to their reliability, and missing or unreliable
evidence is ignored.

Alain de Cheveigne'
Laboratoire de Linguistique Formelle, CNRS / Universite' Paris 7,
case 7003, 2 place Jussieu, 75251 Paris CEDEX 05, FRANCE.
phone:   +33 1 44273633, fax: +33 1 44277919
e-mail:  alain@linguist.jussieu.fr

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