On Thu, 29 Mar 2018, Fred Cisin via cctalk wrote:
On Thu, 29 Mar 2018, geneb via cctalk wrote:
I'm probably WAY over simplifying this because I don't have a grasp of the
optics involved, but wouldn't it be possible to get a good image of
individual pages on a microfiche by using a DSLR with the right lens and a
CNC X/Y table made from one of the large (8x10) LED illuminators used to
treat SAD? The lights are pretty bright and are under $50.
Getting EVEN illumination throughout the frame will still be an issue. BIG
issue for photographic images, but still a minor issue for bitonal text and
schematics.
Theoretical ideal is a point source with collimating "condenser" lenses (like
the top half of an enlarger). BUT, for this, a diffuse light source or an
added diffuser MIGHT be adequate. Particularly for bitonal, where half-tone
density, or color balance, is not significant.
The unit I saw last week was very even. The person that owned it uses it
for studio lighting for video production.
The X/Y table build would be very simple and cheap to build.
For you, maybe. I'm a little overwhelmed contemplating that part of the
project. Even the film holder is a little work.
Which is why I was suggesting gutting a fiche reader for those mechanical
parts, and then adding positioning mechanisms.
The X/Y table is probably the simplest part of the build - every part of
it is a solved problem, from the motion gantry to the controller. It
could be driven by an Arduino Uno and a pair of Pololu Stepper Drivers
connected to a pair of 1.8 degree NEMA17 steppers. The gantry could be
made from 3D printed carriages equipped with 608 skate bearings riding
atop rails made from 1/2" EMT conduit.
The camera system is WAY outside my wheelhouse, but I'd be happy to work
with someone to get an X/Y gantry built. I've got plenty of idle 3D
printers and tons of unused skate bearings. :)
g.
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