Unfortunately, the sound samples in the article are not doing IRENE a
great favour: Sure, there is much less crackle, but the level of the
IRENE sample is significantly lower (rendering the S/N ratio probably
about the same), and it has much higher wow.
Neat idea, nevertheless, and one with great potential.
Marcos
Farris Wahbeh wrote:
> Here's a nice article on IRENE published in UC Berkeley's "Science Matters"
> journal.
>
> The link to the article has neat sound scan pictures and links to sound
> samples:
> http://sciencematters.berkeley.edu/archives/volume4/issue30/story1.php
>
> More info on IRENE is here: http://irene.lbl.gov.
>
>
> Rescuing Recorded Sound from Silence
>
> by Kathleen M. Wong
>
> Researchers Carl Haber and Vitaliy Fedayev of Lawrence Berkeley National
> Laboratories working on IRENE. credit: LBNL
>
> While listening to National Public Radio in 2000, Carl Haber learned that
> the Library of Congress had a big problem. The Library's audio collection,
> which spans the 130-year history of recorded sound, includes the soaring
> tenor of Enrico Caruso, the speeches of Teddy Roosevelt, and the voices of
> Native Americans from now-vanished tribes. These echoes of a bygone era were
> recorded on media such as wax cylinders and shellac and lacquer discs. But
> many are now too fragile to play in their original format; the pressure of a
> stylus or phonograph needle could cause irreversible damage. Others are too
> broken, worn or scratched to yield high-quality sound. The archivists needed
> a means to preserve the recordings without injuring them further.
>
> A physicist with Lawrence Berkeley National Laboratory (LBNL), Haber was
> developing subatomic particle detectors to be used at CERN in Geneva,
> Switzerland. This involved using digital cameras and robots to place each
> delicate detector in precisely the right place. In a flash of insight, Haber
> realized that an optical scanning system could solve the Library's quandary.
>
> Millions of historical sound recordings such as this wax cylinder are in
> need of preservation in the United States alone. credit: courtesy Carl Haber
>
> "I had phonograph records as a kid, so I knew sound was stored in a
> mechanical profile. I realized that we could use images to figure out in
> detail what the groove actually looked like, and use a computer to calculate
> the sound. I thought that might be a way to get around the problem of things
> being delicate and damaged; you wouldn't have to touch them," Haber says.
>
> Haber already had access to a machine that could make high-resolution
> digital scans. Postdoctoral fellow Vitaliy Fadeyev wrote a computer program
> to control the turntable and translate the images into sound.
>
> Haber used a narrow beam of light to illuminate the record's surface. The
> flat bottoms of the grooves and the spaces between tracks appeared white;
> the sloped sides of the grooves, scratches and dirt looked black. The image
> was then analyzed by computer. The program found the edges of each groove by
> focusing on areas of high contrast. It could correct areas where scratches,
> breaks or wear made the groove wider or narrower than normal.
>
> A digital scan of phonograph grooves taken by IRENE. The side-to-side
> wiggles of the groove contain the audio information. credit: Carl Haber
>
> That first test was agonizingly slow. Forty minutes of scanning was required
> to obtain just one second of audio. But it provided what the scientists
> needed-proof of principle. And the scan played far more cleanly and clearly
> than the worn original disc.
>
> Haber and Fadeyev wrote a paper describing the device and sent it,
> unsolicited, to the Library of Congress. The next thing Haber knew, he had
> an invitation to visit the Library to talk about the technique. By 2004,
> Haber and Fadeyev were developing ways to scan discs and cylinders more
> efficiently.
>
> The two types of media presented very different problems. On antique
> monaural discs, sound is recorded in horizontal wiggles of the record
> groove. On cylinders, sound is recorded in the vertical plane-the depth of
> the groove.
>
> Millions of historical sound recordings such as this wax cylinder are in
> need of preservation in the United States alone. credit: courtesy Carl Haber
>
> "With discs, we used a camera to image them at high resolution in two
> dimensions. Once we understood how cylinders were recorded, we realized we
> had to measure the third dimension (3D) as well," Haber says.
>
> In 2005, LBNL engineers Earl Cornell and Robert Nordmeyer joined the
> project. With the Library's urging, the team concentrated on producing a
> dedicated disc scanner. Dubbed IRENE (after the Weavers' "Good Night,
> Irene," the first disc the team scanned), the device was installed at the
> Library last summer for evaluation and needs just four seconds to scan one
> second of audio.
>
> The group is now refining a device that scans in 3D. The device is based
> upon a type of confocal microscope. White light directed at the surface of a
> cylinder or disc passes through a lens. But the lens is imperfect by design;
> though it splits the light into its component colors, each color comes into
> focus at a different depth. The color of the reflected light reveals the
> height of the scanned point. The computer assembles these points into
> profiles for each groove and translates the data into sound.
>
> A digital scan of phonograph grooves taken by IRENE. The side-to-side
> wiggles of the groove contain the audio information. credit: Carl Haber
>
> The current 3D scanning process takes 20 hours to record one minute of
> sound. But a new version of the confocal scanner, developed for the dental
> industry, should reduce that to about 10 minutes.
>
> A half-dozen physics and engineering undergraduates from UC Berkeley have
> been instrumental in speeding the project along. "Students can apply the
> kinds of techniques they learn in classes about statistics, mathematical
> analysis and signal processing to a project they can really get their arms
> around," Haber says. A Berkeley graduate student in linguistics is poised to
> join the project later this summer.
>
> UC Berkeley's Phoebe Hearst Museum and Native Americans are among those who
> could benefit the most from IRENE and its sister 3D scanner. In the early
> 1900s, UC Berkeley anthropologist Alfred Kroeber and colleagues recorded the
> legends, songs, customs and voices of dozens of California Indians on some
> 3,000 one-of-a-kind wax cylinders. Many of these tribes and languages have
> since died out or are on the verge of extinction. The LBNL group is now
> collaborating with linguist Andrew Garrett and Victoria Bradshaw of the
> museum to digitize the Kroeber recordings. Remastering these cylinders could
> help new generations of native peoples study their ancestral customs and
> tongues—and help carry the sounds of the past into the future.
> Sound Samples
--
Marcos Sueiro Bal
Audio/Moving Image Project Archivist
Preservation Division
Columbia University Libraries
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