Hi Michael,

some kind of semi-automatic procedure for rebuilding legacy
hardware would be a nice option. Here's what you need to do:

1. Take a picture of your board using a flatbed scanner.
2. Chance the color of the board plane to white and of the
   traces to black; save as BMP file.
3. Use one of those converters mentioned in the
   "BMP-to-gerber" threads.

This was the good news. Now back to the real life.

I think the problems getting this into operation are so big
that (almost?) noone takes this procedure into consideration:

1. Depending on the board pattern it is hard or even impossible
   to get a sharp, high-contrast image.
2. You will have a hard work post-processing your picture to
   a black/white bitmap.
3. Dimensions (and maybe the aspect ratio) gets lost when saving
   it as a bitmap file (it depends on the bitmap resolution).
   Rescaling it back to the original outline may drive you nuts
4. With big, detailled bitmaps you will spend a hard time in
   converting them to gerber or pdb data. The conversion will
   bring myriads of tiny tracks and artefacts into the pcb,
   which you have to remove/redraw in post-processing.
5. Double-sided boards are a crap if you want both sides to match.
5. No matter what you do, you will not get a re-editable artwork
   file, which you can cross-check with a schematic.

Maybe with small, crude, single-sided boards and with some
effort you will have some success, but those boards are
easily to be redrawn in the "old-fashioned" way anyhow ;-)

I will not say that it is impossible to get useful results
from such kind of reengineering. But you will need highly
sophisticated tools to hit the jackpot. I disbelieve you
will find them.

Regards, Ralf


Ralf Guetlein
Biotest Medizintechnik GmbH
Industriestrasse 19
D-63755 Alzenau
Tel. +49 6023 9487-42
Fax. +49 6023 9487-33

----- Original Message -----
From: "Robison Michael R CNIN" <[EMAIL PROTECTED]>
Sent: Thursday, October 18, 2001 3:33 PM
Subject: [PEDA] gerbers from a scan ??

> hello,
> i guess our customer on this board rebuild job is happy with us
> and has given us a bunch more boards to do.  over half of them
> are simple two-sided boards.  with no existing gerbers, up til
> now i've been recreating these in protel with a stripped board and
> a set of calipers.
> this issue has been sitting on the backburner for me a while, but
> bob wolfe mentioned something close to it and now my interest
> is piqued.  there is another facility here on base that can take an
> existing board that's stripped and somehow scan or photograph
> the surface and generate gerbers from that.  they want me to go
> over and check it out and give them an idea of whether this is a
> good idea and what kind of problems might be involved with this
> process.
> my question:  what am i likely to find when i go over there?  i'm
> going to assume that there is some scanning or photographic
> hardware thats associated with some software program that
> converts a raster image into the vectorized gerber files.  are you
> guys familiar with this kind of setup?  what are some of the software/
> hardware setups employed for this?  surely its better than me sitting
> here re-creating the boards by hand.
> any comments will be appreciated.
> thanks, miker

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