Re: [Help-gsl] connected component analysis with GSL?

[Carlos Medrano]

Hi,

 Well, this is not a GSL solution, but may be the following can help you. Once 
I had a similar problem. I was working with openCV and I couldn't find a  
function like the 'bwlabel' function of Octave or Matlab. May be it is 
implemented in openCV, but ... I spent some time and I didn't get it.

 So I just took the function bwlabel.c from Octave (well, from its image 
processing package) and I adapted it from the openCV data type. It took me a 
few hours. I was interested only in binary input images. You should check the 
behaviour with gray images.

 Best regards:

Carlos Medrano

On Wednesday 10 March 2010 18:02:15 address@hidden wrote:
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>    1. connected component analysis with GSL? (Dan Lenski)
>    2. connected component analysis with GSL? (Dan Lenski)
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> ----------------------------------------------------------------------
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> Message: 1
> Date: Tue, 9 Mar 2010 15:58:24 +0000 (UTC)
> From: Dan Lenski <address@hidden>
> Subject: [Help-gsl] connected component analysis with GSL?
> To: address@hidden
> Message-ID: <address@hidden>
> Content-Type: text/plain; charset=UTF-8
>
> Hi,
>
> I am trying to write a program to clean up small dust specks in scanned
> TIFF images.  I wrote this first in Python/SciPy, but it's rather slow
> unfortunately.
>
> I was hoping to reimplement it using Libtiff and GSL, in C.  I was
> wondering if GSL has any routines for connected component analysis.
> E.g., given a matrix/array that looks like this:
>
> A = [[ 0 1 1 0 1
>        0 0 2 2 2
>        1 1 1 1 0
>        0 3 3 2 2 ]]
>
> ... I'd like generate a labeled structure that looks something like this:
>
> labels = [[ 0 1 1 0 2
>             0 0 3 3 3
>             4 4 4 4 0
>             0 5 5 6 6 ]]
>
> ... where each contiguous (4- or 8-way connected) region of non-zero has
> been given its own label.
>
> I googled around, but did not find much.  Does anyone know of some open-
> source code to do this in GSL?  I suppose I could re-invent the wheel,
> but would rather not if I can avoid it.
>
> Thanks for any pointers!
>
> Dan
>
>
>
>
>
>
> ------------------------------
>
> Message: 2
> Date: Tue, 9 Mar 2010 17:48:56 +0000 (UTC)
> From: Dan Lenski <address@hidden>
> Subject: [Help-gsl] connected component analysis with GSL?
> To: address@hidden
> Message-ID: <address@hidden>
> Content-Type: text/plain; charset=UTF-8
>
> Hi,
>
> I am trying to write a program to clean up small dust specks in scanned
> TIFF images.  I wrote this first in Python/SciPy, but it's rather slow
> unfortunately.
>
> I was hoping to reimplement it using Libtiff and GSL, in C.  I was
> wondering if GSL has any routines for connected component analysis.
> E.g., given a matrix/array that looks like this:
>
> A = [[ 0 1 1 0 1
>        0 0 2 2 2
>        1 1 1 1 0
>        0 3 3 2 2 ]]
>
> ... I'd like generate a labeled structure that looks something like this:
>
> labels = [[ 0 1 1 0 2
>             0 0 3 3 3
>             4 4 4 4 0
>             0 5 5 6 6 ]]
>
> ... where each contiguous (4- or 8-way connected) region of non-zero has
> been given its own label.
>
> I googled around, but did not find much.  Does anyone know of some open-
> source code to do this in GSL?  I suppose I could re-invent the wheel,
> but would rather not if I can avoid it.
>
> Thanks for any pointers!
>
> Dan
>
>
>
>
>
> ------------------------------
>
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