[PD] vowel recognition

[Andy Farnell]

On Tue, 11 Mar 2008 09:19:08 +0100
Bryan Jurish <moocow at ling.uni-potsdam.de> wrote:

> moin Marius, moin list,
> 
> sorry, haven't tried it yet -- i'm more interested in getting funny
> noises out of pd than into it ;-)  Maybe Andy Farnell has done something
> along these lines?


No, I've nothing much to offer here except that LPC (linear predictive coding)
is one way I believe vowel recognition can be done.

Perry and Eduardo Miranda both mention it in their textbooks in this
context and I'm pretty sure there's a whole stack of papers out there
from speech recognition people that will point you in this direction.

LPC delivers the pitched or noisy component, plus a residual error, plus
a profile of a filter that would reconstruct the orginal signal if the
pitched/noisy part were subjected to it. I can't remember exactly how this
works, but there is a way to turn the LPC analysis into the coefficients 
for this filter. In Csound it works as an analysis resynthesis pair.

I think only three strong poles need to be identified then pattern matching
to the spacing of these formants should give you the vowel,
independently of the voice age/gender/louness etc when you look at the
ratios (say the first and second distance vs the first and third)






> 
> Speculating wildly (e.g. without any experience in vowel detection), I
> think [fiddle~] probably won't work on its own: it's designed to detect
> the fundamental frequency (f0), whereas vowels will differ primarily in
> the formants: maybe an fft approach would work?  or perhaps you could
> have several instances of [fiddle~], tweaking the parameters such that
> each detects a single formant?  ... just wild speculation ...
> 
> marmosets,
> 	Bryan
> 
> On 2008-03-11 00:35:42, marius schebella <marius.schebella at gmail.com>
> appears to have written:
> > hi,
> > I wonder if anyone did vowel recognition with Pd. Maybe ed kelly? or 
> > brian j.?
> > can it be based on fiddle~ or does it neeed more/other objects/technology?
> > marius.
> 
> -- 
> Bryan Jurish                           "There is *always* one more bug."
> jurish at ling.uni-potsdam.de      -Lubarsky's Law of Cybernetic Entomology
> 
> 
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