[Insight-users] Discrete vs. RecursiveGaussianImageFilter?

[Luis Ibanez]

Hi Eve,

These comments on the software guide were based on experiments that Paul
Yushkevich
ran several years ago comparing the multiple Gaussian smoothing filters
available in ITK.

Unfortunately we made the mistake of not keeping the test as a permanent
part of
the toolkit, so we will have to repeat that experiment in order to answer
your question
properly.

My recollection is that a small kernel was in the range of "5x5x5",... but I
may be wrong.

This is the kind of experiment that could make a very interesting paper for
the
Insight Journal: take the two filters and compare their computation time for

equivalent sigmas in images of different sizes.

You could setup this test by mixing the code of the two following examples:


   - SmoothingRecursiveGaussianImageFilter.cxx
   - DiscreteGaussianImageFilter.cxx


that you will find in the directory

            Insight/Examples/Filtering

In order to measure computation time you can use the class


   - itkTimeProbesCollectorBase


Please let us know if you find any problems when setting up
this test.


     Thanks,


         Luis


------------------------------------------------------------------------------------
On 7/25/07, Eve <evelyn_heyes at homeworking.org> wrote:
>
>
> Hello,
>
> According to ITK-Guide, "when the Gaussian kernel is small, the
> itk::DiscreteGaussianImageFilter filter tends to run faster than
> itk::RecursiveGaussianImageFilter". For a 200*20*200 volume, how small a
> kernel is consider "small"? i.e. what range is considered small? Also,
> what
> are the (different) effects of "SetUseImageSpacing()" if the spacing
> between
> slices is large vs. small?
>
> Thanks,
> Eve
>
> --
> View this message in context:
> http://www.nabble.com/Discrete-vs.-RecursiveGaussianImageFilter--tf4148711.html#a11802231
> Sent from the ITK - Users mailing list archive at Nabble.com.
>
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