[gnuspeech-contact] Status of GnuSpeech

[D.R. Hill]

Hi Lee,

Thanks for your query.

Articulatory synthesis is a method of producing synthetic speech from a 
waveguide (or "tube") model of the human vocal & nasal tracts. 
Conventional synthesis either takes small segments of real speech (usually 
represented in Linear Predictive Coded form, with the pitch effect 
removed) and concatenates them, before re-imposing some pitch (intonation) 
contour; or sends parameters to a set of bandpass filters, to vary their 
frequencies, and feeds a voicing waveform and/or suitable noise through 
them (either in parallel or in series), with further filtering to account 
for things like the radiation impedance of the lips.  DECTalk, as used by 
Stephen Hawking is an example of the latter, and the method dates back to 
the 50s, and is called "formant synthesis".  The concatenation method is 
called "concatenative synthesis".  Both methods have their problems and 
advantages.

You will find papers relevant to understanding the details and advantages 
of "articulatory synthesis" based on the tube model on my university web 
site amongst the papers that are available there:

        http://www.cpsc.ucalgary.ca/~hill

You can also find a wealth of excellent information by going to Julius 
Smith's website at Stanford University.

        http://ccrma.stanford.edu/~jos

and link elsewhere from there, if necessary.

We call the "tube model" an "articulatory synthesiser" because it is 
controlled using what is called the "Distinctive Region Model" due to Rene 
Carre at the ENST in Paris who built it on the basis of work in 1973 at 
the Speech Technology Lab, KTH, Stockholm by Gunnar Fant and his 
colleagues.

The essence of the control method is to vary the diameter each of eight 
"distinctive" regions of the tube as happens in the real vocal tract.  The 
regions are defined by the "formant sensitivity analysis"carried out by 
Fant which showed that the effect of constrictions in each region have a 
specific, independent effect of the values of the three "formants" or 
resonant peaks in the speech spectrum that determine the identity of the 
speech sounds.  Carre showed that these regions also correspond fairly 
closely to the distribution of the articulators in the real human vocal 
tract, so that our articulators are appropriately positioned to effect 
just the constrictions required for the DRM model.  There is provision in 
our scheme for mapping the DRM regions onto specific articulatory gestures 
but, so far, we have simply used the DRM regions directly, togther with 
information on rhythm and intonation derived from research at the U of C 
and other places.  Those who have heard the speech comment that it is the 
best they have heard, though in fact I think it still needs a lot of 
improvement -- we only have a first cut at the "posture"  (phone 
articulation) data so far.  The same listeners tell us it is much less 
tiring to listen to than conventional synthetic speech (by which they mean 
formant synthesis -- concatenative synthesis tends to be confined to 
rather short utterances for things like telephone intercepts, in 
practice).

The "articulatory" synthesis allows a wide variety of different voice 
types to by used, simply by varying things like the tube length, pitch, 
breathiness (especially for female speech) and so on, and the rhythm and 
intonation models are based on a generalised abstraction of real speech.

I hope this meets you initial needs for information.  I attach a .snd file 
that provides a comparison of the word "hello" spoken by male, female and 
child voices emanating from the tube.  If your system doesn't like .snd 
files, just change the extension to .au -- they are the same.

I should add that we have a complete database and system capable of 
producing continuous speech running under NeXTSTEP 3.x, and this is what 
is available under a GPL check the CVS repository) and what is being 
ported to other systems, particularly GnuStep and OS X.

Unfortunately, GnuStep is not widely available and somewhat immature 
still, so progress on that is slow -- the various system components 
include some that are GUI-intensive.  I am considering building from 
scratch for Linux, without using GnuStep, but that is a *major* 
programming effort.

Thanks you for your interest.

All good wishes.

david
-----
David R. Hill, Computer Science, U. Calgary  | Imagination is more
Calgary, AB, Canada T2N 1N4 Ph: 604-947-9362 | important than knowledge.
address@hidden OR address@hidden|         (Albert Einstein)
http://www.cpsc.ucalgary.ca/~hill            | Kill your television!
----
Lee Butterman wrote:


> From address@hidden Tue Sep 28 07:59:15 2004
Date: Tue, 28 Sep 2004 09:54:22 -0400
From: Lee Butterman <address@hidden>
To: address@hidden
Subject: status of gnuspeech

Hi, I was wondering about two things.  First, I've never heard articulatory
synthesis before, so I was wondering if you had any pre-synthesized examples
just to demonstrate how it sounds.  Secondly, what's the status of gnuspeech?
Will there every be, say, an MBROLA-like interface, where you've got  some
detachable module that takes phonemes (along with tables/models of their
positions in the mouth?) and then synthesizes speech?

Thanks so much,
Lee

helloComparison.snd
Description: Basic audio