[Insight-developers] ImageToHistogramFilter issue

[Iván Macía]

Hi David,

For our applications we have been using itk::ScalarImageToHistogramGenerator
with the new Statistics framework, since we suffered the overflow issue with
the previous version. The corresponding multi-component version seems to be
itk::ImageToHistogramGenerator.

Having a look at the documentation of ITK 3.20 I don't clearly see what is
the difference between itk::ImageToHistogramGenerator and
itk::ImageToHistogramFilter. Furthermore, the API for the later seems to be
a bit obscure (SetInput1()? SetInput3()? SetInput5()?). In general there is
a lack of documentation of these filters.

It seems like itk::ImageToHistogramGenerator is not part of ITK 4.0, is this
true? I have been very busy lately and need to put up with all the ITK v4.0
and git stuff but need some time since it seems to be hard :S 

Best regards

Ivan



-----Mensaje original-----
De: insight-developers-bounces at itk.org
[mailto:insight-developers-bounces at itk.org] En nombre de David Doria
Enviado el: martes, 16 de noviembre de 2010 23:21
Para: Insight Developers
Asunto: [Insight-developers] ImageToHistogramFilter issue

Hi all,

I am trying to use the ImageToHistogramFilter. I see some unexpected
things when I create an iterator to traverse the histogram. First, it
seems to only traverse the first component. That is, I see indices of

0, 0, 0
1, 0, 0
2, 0, 0
...
0, 0, 0 (this repeats exactly from the beginning, rather than
incrementing  the 2nd or 3rd component)
1, 0, 0
....

The histogram cell centers (the iterator's .GetMeasurementVector())
also seem to follow the pattern of the index in that the second two
components don't move from zero.

Also, my query for "how many red pixels are there?" returns 0, when I
would expect 2 (there are two red pixels in the example input image).

Here is my demonstration of the problem:
http://www.vtk.org/Wiki/ITK/Examples/Broken/Statistics/ImageToHistogramFilte
r

Any thoughts? Has anyone successfully created a 3D histogram from an
image after the Statistics overhaul?

Thanks,

David
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