7 Dec
1998
7 Dec
'98
11 p.m.
>not critical that it be pretty - just readable. I
wouldn't be surprised
>if you could rig up something like this pretty easily yourself; pick up
>one of the fiche viewers that they can't give away at most university
>and government auctions, get a cheap flatbed scanner (even pretty good
>new ones can be had for under $100), take the mechanism out of the case,
>and bolt it to the front of the fiche viewer. You'd have to remove or
>disable the light source, since the bulb in the fiche viewer provides
>the illumination. I don't think you'd even have to mess with the focal
>length much; the fiche viewers normally do a rear-projection on frosted
>glass, and the scanner is set up to focus on a sheet of paper an inch or
>two away from the sensor, so with a spacer or two it should just work.
>That sounds like an interesting enough project that I might even build
>one if I had anything on fiche to scan. (I'm more interested in getting
Yesterday I tried a similar way as described above. I took a sheet
of Butterbrotpapier (sorry, I dont know any translation, its a kind
of semitransparent paper used to cover sandwitches - Butterbrote :)
put it atop the scanner, disabled the lamp (I had to disable the lamp
only during the 'real' scan, since my scanner always add a 'white
adjustment' before scaning, so the the lamp is only temporary
disabeled AND I had to fake the lamp controll signals ... this took
me almost three hours to figure out how they controll it), added one
mirror and used a fiche projector to display one page right on the
paper screen.
<pre>
mirror
/ light --
/+- - - - - - - - - - - - - I projector with fiche
/ : --
/--------------- paper
######## scanner
</pre>
Since the fiche information was only b&w, the
contrast was no problem at all. This method
should work well for low resolution scanners.
You could do it even without changing the scanner at
all. take two
mirrors and build a 'hat' for the fiche - the light will pass the fice at
one side, get reflected by the mirrors and be passed back, now thru
the fiche. This works quite will since in most scanners the light runs
some one or two cm in front of the scannerline. Of course the 'hat'
has to be adjusted to this angle. It works quite well for pictures, but
for a fiche you might need a _real_ high resolution scanner. If the
fiche document is made from ordinary 'typewriter' papers or drawings
(like most of my 1960s/70s mainframe fiches) the resolution should
be better than 1200 dpi to get an idea of the text. If small parts are
to be viewed, >3000 is needed. One advantage of fiches is still the
_real_ high resolution :)
Postscript:
<pre>
frontview (in direction of scanner movement)
/\mirrors
/ \
/+--+\ way of light
/ I I \
/ --- I \ fiche
------------ scanner
sideview:
+-------+ mirrors
I I\ I way of light
I I \ I
I I \ I
I ----- * fiche
----------- scanner
>>>>>> movement
* = this side
has to be a bit higher - the 'hat' is
lifted here to fit the lamp angle of the scanner -
this needs some trieal and error. Its also for scanners
with the lamp infront of the scan line - otherwise the
oherer side has to be lifted.
Sorry, but it's hard to do high resolution 3D ASCII
drawinge :)))
Gruss
Hans
--
Ich denke, also bin ich, also gut
HRK