[Wikisource-l] [Commons-l] Digitisation equipment

[Lars Aronsson]

Gregory Maxwell wrote:

> For digitizing what?

Exactly, that's the first question.

> Archive.org digitizes books using a pair of canon 1Ds (? perhaps 
> it was a 5D? In any case the 5DII would be sufficient now) on a 
> custom stand with a hacked up copy of gphoto2 to actuate the 
> cameras.

That's Brewster Kahle doing things many years ago (2002? 2003?). 
Today, a much cheaper low-end digital SLR, or even compact cameras 
will give you the needed 10 or so megapixels.  But again, if you 
need to pay your staff, a ten times more expensive camera might 
easily pay its own cost in increased speed, or increased shutter 
lifespan.

> I'm not sure how they're dealing with curvature (I think they 
> just may lay a glass plate on the pages), but it would be easy 
> enough to solve using a laser pointer with a pattern generating 
> holographic grating and a second exposure to capture the page 
> distortion and some fairly simple software processing after the 
> fact.

The Internet Archive apparently uses a fixed glass, and lowers the 
book cradle to turn pages, http://aipengineering.com/scribe/

Other designs have a fixed book cradle and lifts the glass, e.g. 
the Atiz DIY, http://diy.atiz.com/

I thought the Internet Archive design was very clever, since it 
keeps a fixed distance from lens to book surface (beneath the 
glass), until I saw the bkrpr.org where you just lift everything. 
That's a design for 2009! I haven't tried to build one myself yet.

----

However, you can capture lots of books (that can be opened fully) 
with a single camera, laying the book flat on a table with a glass 
on top.  That's just like a flatbed scanner (but much faster) 
turned upside down.

In January 2008, I used a 10 megapixel Canon EOS 400D (Digital 
Rebel XTi) with a 50 mm lens to shoot this, laying flat on a table 
under a glass, http://runeberg.org/stridfin/0226.html

On that webpage, the image is reduced to 120 dpi (1.2 megapixel), 
but the original is 300 dpi (7.5 megapixel).  The map shown is 
reused in http://en.wikipedia.org/wiki/Battle_of_Alavus

That's an example of how one specialized book can be very useful 
for a limited Wikiproject. This book was published in 1909 for the 
100th anniversary of the Finnish War (1808-1809), and digitized in 
2008 for the 200th anniversary.



-- 
  Lars Aronsson (lars at aronsson.se)
  Aronsson Datateknik - http://aronsson.se

  Project Runeberg - free Nordic literature - http://runeberg.org/