[Image-SIG] experimental data diagram digitalization

tomislav_maric@gmx.com tomislav.maric at gmx.com
Fri Nov 26 11:45:09 CET 2010

Hi everyone, 

I need to digitalize a diagram of experimental data. I have been reading the documentation of the Python Imaging Library, and I'm thinking that I can approach my problem in the following way:

1) Create a .png of the diagram I find in the literature (.pdf articles, or theses). 
2) Clean up the diagram (remove the axes, the text and leave only the data that I am interested in). 
3) Read the image. 
4) Apply a filter that will result in only those pixels that are non-white (pick up the experimental data). 
5) Scale the result data of the filter (in pixels) to the actual coordinates in the image in milimeters. 
6) Scale the milimeter coordinates to the actual scale of the diagram (read from the original .pdf), to get the
   true coordinates (in my case, I have time in seconds and pressure in kPa). 

Can this be done with the Python Imaging Library + some additional python coding?

The other option would be to use inkscape to export the path into .svg and manipulate (scale) it with some python-XML library.

Can anyone give me some advice on this issue? 

Thanks in advance, 

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