I have a photograph of an item that is made of flat metal sheet
about 1/8" (the thickness is irrelevent).  The piece is about 3'x2'
and is cut out in the shape of a cow.  The shape has many straight and
curvy edges.  I want to scan the photo and then use probably photoshop
to find edges and then convert the resultant line drawing into
vector format.  My goal is to use the vector drawing to feed into a
laser cutting m/c to cut out the shape.  I would like to know:

Will photoshop be a good tool to find edges in the picture or convert
the outline of the pic into vector format?  If not can you
suggest a better way to achieve it?  Also, if photoshop is the way to
go, can you suggest how do i achieve it in photoshop.

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Clarification of Question by sundari_haseena-ga on 03 Aug 2005 15:24 PDT

I do not have a scanned copy of the pix.  But here is a link to an
hand dranwing that might help explain the pix.

http://pg.photos.yahoo.com/ph/shirish_kumar/detail?.dir=/1c53&.dnm=88b3.jpg&.src=ph

Now this hand drawing is very clean, but the scanned pix needs some
clean up such as removing shadow before determining the edges.  Also,
I should be able to scale the image i.e. if I increase the size all
the parts should increas proportionaly.

Thanks.
-Shirish

Well i have figured out a way i can achieve this. but for best results
can maybe post the picture online or email it to me. i would convert
it for you and include directions for future reference. Otherwise if
you cannot do that, please describe the photo and how you want the
vector drawing to be, do you want simple cut out lines like a trace?

Well the best i can give you is photoshop and fireworks will be able
to do what you want with some experience in those programs. It wont be
done with simple follow to do instructions at least i am not personaly
capible of giving them with the unlimited possibilies of what the
photo may need to be prepped for a drawing. my offer to you is to scan
the image possible and let me reconstruct it.

Dear Sir,
One idea is to lay the cow-shaped metal piece down on a blank sheet of
ANSI D sz paper ( 34"W x 22" H) or Esz ( 44"x36"). Then use a drafters
pencil to carefully trace around the metal cow. This will leave the
outline of the cow on the blank paper. Then, if you have a CAD program
that will let you digitize using the Mouse, you could open a new file
in the CAD program, set up a D size page format, and then Digitize all
along the outline of the cow. This will effectively create an image of
the cow in the CAD file, and the line elements will all be vector, not
raster.

The easist tool to use for this is Corel Trace. You can download and
try a fully functional copy of this from
http://www.corel.com/servlet/Satellite?pagename=Corel3/Downloads/Trials
(Trace is part of the CorelDRAW Graphics Suite 12). Corel is an
excellent vector-based graphics suite and is widely supported by
various cutters and cutting applications.

You should be able to export the results to a variety of formats -
specifically EPS and DXF are the two that the application running your
laser cutter should be able to work with.

If you want to use Photoshop, you can create selections based on the
areas you want. Using the Magic Wand in combination with the Magic
Lasso with a relatively low Tolerance setting (in the 1-32 range) will
probably give the best results. As you select, I recommend saving it
along the way (Select>Save Selection). Once you have created your
selection, open the Paths Window and use the Convert Selection to Path
button to convert your selection to a path (hold down the ALT key as
you press the button to set the Tolerance for fitting the path).
Finally, once you have created your path, choose File>Export>Paths to
Illustrator to export an AI file (the AI file is basically the same as
an EPS).

My last note, though, is that Corel Trace will give you better quality
and is much easier than using Photoshop for converting a raster image
to a vector one.