Identifying filled circles in a scanned image

[John J. Lee]

Douglas Douglas <replaceafill at yahoo.com> writes:

> Hi everybody.
> 
> I have a paper form that I scan into an image. My user fills some circles in
> this paper form using black ink. Every form has ten rows with five circles each
> and the user fills only one circle for each row.
> 
> I was wondering if I could use the Python Imaging Library to process these
> forms. I know the Image class is really powerful, but I can't think of a way of
> how to locate wich circle was filled.
> 
> Could anybody please give me an advice on this?

I think in astronomical / biological circles this kind or problem is
known as "blob analysis", or something like that (certainly I remember
the word "blob" correctly ;-).

Try one of the numpy / numarray / Numerical Python / SciPy lists,
bound to be people there who know a lot about this sort of problem,
and your problem sounds quite a bit easier than the general one.


John