From: malcolm@apple.com
Date: Thu, 13 Jan 94 18:56:43 PST
Subject: Pattern Playback at CCRMA
Message-Id: <9401140256.AA00361@internal.apple.com>

The Stanford CCRMA Hearing Seminar returns this month with both a
retrospective and an update on speech pattern playback.  We've all looked
at spectrograms as a way to analyze sound, and we've all heard about
reading spectrograms.  But can we turn a picture into a voice?  That's the
essense of pattern playback.

I'm very happy to announce that Dr. Frank Cooper will lead the next Hearing
Seminar with a presentation on his original work on pattern playback. 
Frank Cooper built the original pattern playback machinery more than 40
(!!) years ago.  Here is what he said about the process in a review
article:
        "Our first step with the Playback was to see whether or not we
could
         produce reasonable phrases and sentences from simple, hand-painted
         spectrograms.  For that purpose, we first copied from spectrograms

         of 'real' speech those parts of the pattern that seemed reasonably
         apparent to the eye and, also, those that impressed us, for other
         reasons, as likely to contain linguistic information.  We were
         pleased, and perhaps a little surprised, to discover that, with a
         manageable amount of trial-and-error editing, these patterns
         produced fairly intelligible speech."
His machine used a light source to illuminate a line of a spectrogram
painted on a transparent film.  The pitch harmonics were generated with a
separate rotating wheel which interrupted the light source.  The light was
then collected, amplified, and played through a speaker.

Dr. Cooper was director of the Haskins Laboratory and is now retired and
living in Palo Alto.  He's agreed to organize his tapes, talk about his
work, and help us hear these original sounds.  What a great opportunity!

Here are the details:
        Who:    Dr. Frank Cooper (Haskins Laboratory, retired)
        What:   The History and Sounds of Pattern Playback
        When:   Thursday January 20th at 11AM
        Where:  CCRMA Library (Top Floor of the Knoll)
                If needed, we will move downstairs to the classroom so we
                can accomodate more listeners.

This is a rare opportunity to hear some of the really historic (and
valuable) sounds of acoustic science!  If you are at all interested in
spectrograms, or sound processing, you should attend!!!!!  I've got several
papers by Dr. Cooper, please let me know via email if you want a copy.

See you at CCRMA for a really rare and wonderful talk!

-- Malcolm

P.S.  The following week (1/27) I'll be presenting work that Dan Naar, Dick
Lyon, and myself have done on current pattern playback techniques.  We've
been working on techniques for reconstructing sounds from their
spectrograms, cochleagrams, and even correlograms!