Auditory-motivated Gammatone wavelet transform
2014 (English)In: Signal Processing, ISSN 0165-1684, E-ISSN 1872-7557, Vol. 94, 608-619 p.Article in journal (Refereed) Published
The ability of the continuous wavelet transform (CWT) to provide good time and frequency localization has made it a popular tool in time-frequency analysis of signals. Wavelets exhibit constant-Q property, which is also possessed by the basilar membrane filters in the peripheral auditory system. The basilar membrane filters or auditory filters are often modeled by a Gammatone function, which provides a good approximation to experimentally determined responses. The filterbank derived from these filters is referred to as a Gammatone filterbank. In general, wavelet analysis can be likened to a filterbank analysis and hence the interesting link between standard wavelet analysis and Gammatone filterbank. However, the Gammatone function does not exactly qualify as a wavelet because its time average is not zero. We show how bona fide wavelets can be constructed out of Gammatone functions. We analyze properties such as admissibility, time-bandwidth product, vanishing moments, which are particularly relevant in the context of wavelets. We also show how the proposed auditory wavelets are produced as the impulse response of a linear, shift-invariant system governed by a linear differential equation with constant coefficients. We propose analog circuit implementations of the proposed CWT. We also show how the Gammatone-derived wavelets can be used for singularity detection and time-frequency analysis of transient signals.
Place, publisher, year, edition, pages
2014. Vol. 94, 608-619 p.
Continuous wavelet transform, Gammatone function, Auditory wavelet, Vanishing moments, Singularity detection
IdentifiersURN: urn:nbn:se:kth:diva-131268DOI: 10.1016/j.sigpro.2013.07.029ISI: 000327363300063ScopusID: 2-s2.0-84883194522OAI: oai:DiVA.org:kth-131268DiVA: diva2:655190
QC 201402032013-10-102013-10-102014-02-03Bibliographically approved