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[Dave Braze]

Maybe this will help (although I've not actually used it): http://datathief.org/

In the past I've done a similar thing using GSview and Ghostscript, which worked 
but was fairly tedious.

-D

On 2:59 PM, Allen.Windhorn at emerson.com wrote:
> Greetings:
>
> This is a question probably more related to machine vision, but I want
> to digitize a lot of hand-drawn graphs that we have accumulated over
> the years.  I would like to scan them, have a clerical person select a
> line on the graph (maybe in several spots), and get back a set of XY
> coordinates of the line.  (A bonus would be to select points on the
> axes and enter the values to automatically do scaling.)  To confound
> the process, there is a grid on the image, and there are several lines
> which may cross each other at various angles.
>
> My first thought is someone must have had this problem before and
> solved it -- if so, can I adapt your solution?  (There was a product
> available commercially, but it didn't work worth a darn.)
>
> If not, can anyone suggest an approach?  My first thought is to
> set an image threshold to convert it to ones and zeros, then do some
> kind of line-following algorithm that would take guidance from a
> human being.  Fortunately, the desired data form smooth curves.
> It will be hard to discriminate between the line and the grid though.
>
> Regards,
> Allen

-- 

Dave Braze, Ph.D.                           braze at haskins.yale.edu
Haskins Laboratories                       www.haskins.yale.edu/staff/braze.html
300 George Street, STE 900             phone: 1-203-865-6163 x241
New Haven, CT 06511-6624             fax: 1-203-865-8963