This technique has been used for decades by our government to extract
information from noise. One example is submerged submarine communications
where the noise level can exceed the signal level. I believe that one method
is called autocorrelation. I do not have references, but perhaps some of the
older methods have been placed in the public domain.

Jerry hartke

> -----Original Message-----
> From: Association for Recorded Sound Discussion List
> [mailto:[log in to unmask]] On Behalf Of Randy Riddle
> Sent: Thursday, June 21, 2012 10:00 AM
> To: [log in to unmask]
> Subject: Re: [ARSCLIST] audio from pictures
>
> I've thought for some time that there's already a way to do this with
> at least some recordings.
>
> For years, film restorers have used multiple prints of films, taking
> the best quality sections from each that survive, sometime
> substituting small sections in a print that has been damaged.
>
> Why couldn't that be done with recordings where multiple copies survive?
>
> Basically, what the software would do is let you take multiple sound
> files sourced from different copies of the same record. Each will
> have been damaged and degraded in different ways and have different
> patterns of noise.
>
> The software, after synching the recordings, would compare them and
> "toss out" the noise and keeping commonalities between the copies.
> The more copies of the recording you have available, the better the
> result might be, at least theoretically.
>
> Why couldn't this work?
>
> rand
>
> On Thu, Jun 21, 2012 at 9:24 AM, Tom Fine <[log in to unmask]>
> wrote:
> > Hi Steve:
> >
> > I agree with you in general, but I'm talking about recordings where
> analog
> > playback has produced poor results -- for instance the badly worn and
> > super-rare Paramount blues records. No transfer I've heard using analog
> > playback and whatever digi-trix the producer decided to use has produced
> > very good-sounding results.
> >
> > I think the pot of gold at the end of the research rainbow for  non-
> physical
> > playback of grooved media is the ability to "erase" all the noise that
> comes
> > from the media itself, and of damage to the media. Then, in theory (and
> > sometime in the future) you'd just be reproducing the information
> originally
> > cut into the groove.
> >
> > For now, I wouldn't worry about your transfer business (or mine) being
> under
> > dire threat. But I hope I live long enough to see the day when putting a
> > needle to an old groove for critical playback or transfer is considered
> > obsolete.
> >
> > -- Tom Fine
> >