Re: Wavelet discussion (Jont Allen )

Subject: Re: Wavelet discussion
From:    Jont Allen  <jba(at)RESEARCH.ATT.COM>
Date:    Fri, 21 Mar 1997 15:14:19 -0500

Linda A. Seltzer wrote: > > > > Another advantage > > > of wavelet filtering is its property of separating bands with quality > > > factor (Q) constant over the frequency axis, in a way the basilar membrane > > > in > > > the inner ear also resolves frequency bands. This property makes wavelets > > > closer to ear's acoustic pre-processing, on stages before neural > > > processing. > > > > Is the nature of the advantage that (1) a person examining wavelet > > analysis output is observing "how the ear experiences the sound", or (2) > > the method is more economical by ignoring detail that goes beyond > > the resolving properties of the ear, or (3) both? > > I'd be interested in any pointers to journal articles or web site > research presentations or books on this topic. > > Linda Seltzer > lseltzer(at) In my opinion, a big thing is being made of a small thing here. The ear is similar to a bank of 1/3 oct filters. That is all there is to it. Some wavelets also have this property. The problem with wavelets is that their frequency response is not part of their definition. The user does not attend to the frequency response of the wavelet, and therefore, its filtering properties are, well, unknown. This is not an ideal situation. There is a little bit of the Emperor's new clothes syndrome about wavelets I'm afraid. If I'm wrong, I would like to hear about it. Jont Allen

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Electrical Engineering Dept., Columbia University