From: jgoodman@endor.uucp (Joshua Goodman)
Newsgroups: comp.arch,comp.ai
Subject: Re: Voice Recog. on Desktop
Date: 12 Apr 92 05:57:23 GMT
Article-I.D.: das.1992Apr12.055723.13230
Organization: Aiken Computation Lab, Harvard University

First, a few notes.  I tried to redirect this to a more appropriate
group in my first post, but that failed.  Oh well, I tried.

Second, from Andy Glew's description, I think we're talking about the
same system, Dragon Systems' "Dragon Dictate."  I'm not trying to sell
Dragon; I'm just trying to keep the conversation tied to verifiable
facts.  

Third, I concur with everything that Andy has said, and much of what
Rick Smith writes; but Rick Smith seems to be unfamiliar with current
speech technology, and thus has made a few mistakes, some of which are
important.  

Finally, most of the information in here is from a talk I heard months
ago, so accuracy is medium.  You get what you pay for.

In article <1992Apr10.152204.1544@sctc.com> smith@sctc.com (Rick Smith) writes:
>It will also be memory intensive. As I recall, an isolated word
>pattern was an 8x12 array of 16 bit numbers. That's somewhat less than
>6 MB for a 30K vocabulary. And you'll want them changable so they can
>adapt to individual pronunciation and inflection. So that's 6 meg of
>NVRAM dedicated to speech recognition.

Well, Rick is half right.  Dragon uses 8 megs of normal RAM for 30K
words.  

>In an earlier post I underlined the word pattern matching as the big
>problem. Are _all_ 30,000 word patterns available at all times? Does
>it take special hardware to manage these 30,000 words?  I'd really
>want to do parallel pattern checking to do a really big vocabulary in
>real time.

All 30K words are available at once.  There is some use use of
context.  That is, (I think this is right) a context score and a word
match score are combined.  If you want to use a word in an odd
context, you have to pronounce it more clearly.  Since the same is
probably true for people, this seems fair.  In his next paragraph Rick
assumes there is some sort of cheating, based on technology from 15
years ago, and labels this "bait and switch."  That's not fair.

As for parallel pattern checking hardware, there's a simpler method:
good algorithms.  Dragon uses a rapid match algorithm which is
inaccurate, but fast.  It then compares only the words with good
matches using a more accurate algorithm.  This allows real time
performance on regular hardware (386 + DSP board).

>Discrete speech means - that - you - talk - like - a - computer - when
>- talking - to - a - computer. That's slower than the way real people
>talk, so it doesn't compete with normal dictation. There are a whole

Yep, this part is too true.  But they are getting better.  As I said,
it hits 30-40 words per minute.  If you type at 30-40 words per
minute, you may find speech recognition systems competitive, though
there are enough limitations that it's too soon to throw out your
keyboard, yet.  But soon.  Rick and I don't really disagree on this
point.  It's partly that he appears to have a secretary, and I don't. :-)

----------

Andy Glew responded to Rick's post.  He mentioned telephone voice
recognition.  Be aware that recognizing speech over phones is much
harder -- the sound quality is much lower.  Telephone systems will
always lag significantly behind other speech recognition systems.

Andy also mentioned "pen computers."  This is an important point.
Since the fastest you can legibly print is about 30 words per minute
and Dragon already hits that rate and is getting better, and you can
talk _much_ faster than 30 wpm, voice has a big long term advantage
over pen.

Joshua Goodman
--biased source of mostly reliable information
Newsgroups: comp.arch