[Insight-users] co-occurrence matrix

[Luis Ibanez]

Hi Glenn


You don't really need to write much code in order
to  compute a coocurrence matrix in ITK because a
Coocurrence Matrix is simply a 2D Histogram.

The itk::Statistics::Histogram class has been desigened
from the beginning for supporting multicomponent data.
Actually if you look at the Histogram example in the
SoftwareGuide, it is a 2D histogram case:

   http://www.itk.org/ItkSoftwareGuide.pdf

Section 10.1.3, pdf-page 428.

--

You should be fine by just taking your two input images
and composing a Vector image with them. For this you can
use the Compose3DVectorImageFilter:
http://www.itk.org/Insight/Doxygen/html/classCompose2DVectorImageFilter.html


Then, passing this vector image to the ImageToHistogramGenerator:
http://www.itk.org/Insight/Doxygen/html/classitk_1_1Statistics_1_1ImageToHistogramGenerator.html

and you get the 2D histogram at the end, which is exactly
a Coocurrence Matrix. Note that you must define the bin
sizes along every dimension, as well as the min and max
values to cover with the his domain of the histogram.



The pipeline will look like


Image1---+
          |
          V
   Compose2DVectorImage ---> ImageToHistogramGenerator ---> Histogram
          ^
          |
Image2---+



Please let us know if you find any problem,


    Thanks



      Luis




-------------------
Glenn Pierce wrote:
> Hi
> 
> I was wondering what the best way of implementing a co-occurrence
> matrix.
> I was thinking of just using itk::Statistics::ImageToListAdaptor or a
> subclass to loop through the image's 
> pixel values and counting each co-occurrence in a histogram.
> 
> Would there be a better way for itk, with respect to contributing the
> code back to ITK?
> Maybe basing my code on another filter?
> 
> Thanks
> 
> Glenn
> 
> 
> Glenn Pierce
> email: glennpierce@connectfree.co.uk
> 
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