and another:
http://www.laserfocusworld.com/articles/print/volume-51/issue-03/newsbreaks/olympus-microscope-recovers-data-from-damaged-optical-media.html



On 3/27/2015 3:44 PM, Greg Schmitz wrote:
> Here is a link to the original article:
>
> "Utilizing 3-D digital laser microscopy to image damaged optical media."
> By Greg Gogolin, James Jones, and Derek Brower
>
> http://www.qualitymag.com/articles/92183-maximizing-data-recovery
>
>
> On 3/27/15 10:33 AM, Steven Smolian wrote:
>> This is from the Ampex list. I thought some of the ARSC and MLA
>> readership
>> would be interested as well.
>>
>> Steve Smolian
>>
>> -----Original Message-----
>> From: Ampex [mailto:[log in to unmask]] On Behalf Of
>> Bill Ruck
>> Sent: Friday, March 27, 2015 12:51 AM
>> To: Ampex Mailing List
>> Subject: [AMPEX] Survival
>>
>> Saw this today in the March 2015 issue of Laser Focus World. (Yes,
>> I do read strange magazines.)
>>
>> Olympus microscope recovers data from damaged optical media
>>
>> Designed for nanometer-level imaging and 3D measurements, the LEXT
>> OLS4000
>> laser-scanning confocal microscope from Olympus (Center Valley, PA) can
>> provide both visual and height maps of damaged CD and DVD optical
>> media (or
>> acute-angled specimens) and recover data from that media using custom
>> algorithms. With a 405 nm wavelength source, the LEXT OLS4000 has a
>> magnification range from 108X to 17,280X and dedicated objective
>> lenses with
>> high numerical apertures.
>>
>> To obtain usable information from damaged optical media (both
>> factory-pressed and home-burned CDs and DVDs), a highly magnified
>> image of
>> the damaged media is created and a region of consecutive dots and
>> dashes is
>> selected. Although the dots and dashes appear to form concentric
>> circles,
>> they actually form a spiral, so there are no beginnings and endings
>> to the
>> apparent tracks. Each dot and dash is then quantitatively measured.
>>
>> Next, the encoding algorithm used to convert the original data into
>> dots and
>> dashes is reversed. (There are only a handful of encoding algorithms in
>> wide use, and most of these are publicly
>> available.) Even if severe data impact has occurred (significant
>> scratches,
>> chemical alterations, surface destriction, or even a disc broken into
>> multiple pieces), it is still possible to adjust the algorithms to
>> recover
>> data based on measurements obtained by the OLS4000.
>>
>>
>> So it seems to me that the guys now recovering audio from strips
>> coated with
>> iron rust need to invest in something like this for optical media.
>>
>> Bill Ruck
>> San Francisco
>>
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>> Copyright 2015 by the author of the post.
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>
>