[PD] OCR with Puredata?

[Jack]

Le mercredi 01 juin 2011 à 12:51 -0400, Tedb0t a écrit :
> > Is it just me, or it sounds like it's going to take a lot of
> > preprocessing before you can even think of feeding it to a neural
> > network ?
> 
> 
> Black/white thresholding and resolution reduction, that's it.
I also use grey images and it was working fine.
> 
> 
> > Human vision is made of a lot more layers of neurons than we can
> > hope to deal with in artificial networks.
> 
> 
> It sure is.  Luckily you only need a few to do some basic OCR.  You
> could try a grid of something like 10x10 pixels just to start, which
> would require 100 input neurons.  The lower the resolution, the higher
> your error rate will be, but you can find good compromises.
I was working with a grid of 16x16 pixels and it was OK for me.
> 
> 
> > At what angles should characters be recognised ?
> 
> 
> Well, that's the beautiful thing about neural nets—it just depends on
> how you train the net.  If you want the net to be able to recognize
> tilted letters, you can add tilted letters to the training sets.  It
> can affect 
Yep, if you train your NN with angles, deformations, etc. You should get
good results.
++

Jack


> 
> 
> > But making an OCR using ANN is a lot lot more work than using an OCR
> > library. Making a Pd-to-OCR-library interface is less work than
> > making an OCR abstraction library
> 
> 
> Agreed, strongly.  OCR is a really excellent exercise in neural nets
> (look up Self-Organizing Maps or Kohonen networks), but it's a lot of
> work.  It would be faster by far to set up an interface as Mathieu
> suggests.  However, if you want to go through with it anyway, I'd love
> to help!
> 
> 
> It looks like the defacto open ocr lib is
> Tesseract: http://code.google.com/p/tesseract-ocr/  This would be
> great to have in Pd.
> 
> 
> Incidentally, I can't see any reason why Pd would be "bad at it,"
> since the ANN external uses the C FANN library, which is likely what
> any other library would use in the first place.
> 
> 
> ±tedb0t
> 
> 
> 
> On Jun 1, 2011, at 11:49 AM, Mathieu Bouchard wrote:
> 
> > On Wed, 1 Jun 2011, Jack wrote:
> > 
> > > You can do this with the use of artificial neural network (for
> > > character recognition). There are externals for Pd :
> > > http://pure-data.svn.sourceforge.net/viewvc/pure-data/trunk/externals/ann/
> > 
> > Is it just me, or it sounds like it's going to take a lot of
> > preprocessing before you can even think of feeding it to a neural
> > network ?
> > 
> > Human vision is made of a lot more layers of neurons than we can
> > hope to deal with in artificial networks.
> > 
> > At what angles should characters be recognised ?
> > 
> > Which colour on which colour ?
> > 
> > You better settle those things first, so that you can figure out how
> > you can reduce your data beforehand.
> > 
> > But making an OCR using ANN is a lot lot more work than using an OCR
> > library. Making a Pd-to-OCR-library interface is less work than
> > making an OCR abstraction library... and it isn't necessarily
> > because Pd would be bad at it (I don't know about that). It's more
> > because it takes a lot of knowledge to make an OCR library from
> > nearly scratch.
> > 
> > _______________________________________________________________________
> > | Mathieu Bouchard ---- tél: +1.514.383.3801 ---- Villeray,
> > Montréal, QC
> > _______________________________________________
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> > 
> 
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