[Insight-users] co-occurrence matrix

[Luis Ibanez]

Hi Glenn,

Loading your image

http://homepage.ntlworld.com/glenn.pierce/co-occur.png

Into the image viewer

      InsightApplications/ImageViewer

and by setting it to display logaritmic values,
(hit the "L" key several times)( or "h" for help)

It shows that the values are actually spread around
the bright spots. It is still pretty focused, but
the fact is that it is not totally in the diagonal.

That may give you a hint on what's going on with
your program....


   Regards,


      Luis


-------------------------

Glenn Pierce wrote:

> Sorry to bother you again again. Last time hopefully
> 
> I have written a test program to display my co-occurrence values.
> I have attached the program.
> 
> However, the values only appear on the forward diagonal as in
> 
> http://homepage.ntlworld.com/glenn.pierce/co-occur.png
> 
> They should appear throughout the image as in the
> 
> http://homepage.ntlworld.com/glenn.pierce/result.png
> 
> I cant think what the problem is.
> 
> When I'm done maybe I we can add this to the Examples under statistics.
> 
> Thanks alot
> 
> 
> On Tue, 2004-05-18 at 11:17 -0400, Luis Ibanez wrote:
> 
>>Hi Glenn,
>>
>>You can visualize the 2D histogram by first copying
>>its values in an itk::Image.
>>
>>For this you can write a while() loop and use the
>>method
>>
>>       histogram->GetFrequency( index );
>>
>>Then you convert this ITK image into a VTK image
>>using the filter adaptors in
>>
>>    InsightApplications/Auxiliary/vtk
>>
>>and plug this vtkImageData into a vtkImageViewer.
>>
>>
>>---
>>
>>We didnt' change the actual computation of your
>>List of measurement vectors.  More on this in a
>>following email...
>>
>>
>>  Regards,
>>
>>
>>    Luis
>>
>>
>>
>>-------------------
>>Glenn Pierce wrote:
>>
>>> On Sun, 2004-05-16 at 15:11 -0400, Luis Ibanez wrote:
>>> 
>>>>Hi Glenn,
>>>>
>>>>Thanks for contributing your code to ITK.
>>>>
>>>>The class has been added under
>>>>
>>>>     Insight/Code/Numerics/Statistics.
>>>>
>>>>
>>> 
>>> Thanks :)
>>> 
>>>>
>>>>Your VTK question wasn't quite clear.
>>>>
>>>>Do you want to take a VTK image and get a cooccurrence
>>>>matrix out of it using ITK ?
>>>>
>>>>or, do you want to use VTK for visualizing the
>>>>cooccurrence matrix that you computed with ITK ?
>>>>
>>> 
>>> I wanted to visualise the cooccurrence matrix with vtk as a grey scale 
>>> image.
>>> So I would be visualising  the frequency for each "pair of intensity 
>>> values". 
>>> So pairs that have a greater frequency appear as higher intensities in a 
>>> grey level image.
>>> 
>>> In my code I was storing each pair in it's own MeasurementVector. 
>>> However I should have
>>> been increasing the frequency for pairs that are the same. Was this 
>>> changed ?
>>> 
>>> 
>>> Thanks for the help.
>>> 
>>> Much appreciated
>>> 
>>> 
>>> Glenn
>>> 
>>
>>
>>