[Insight-users] Re: Insight-users Digest, Vol 15, Issue 37

[Bryn Lloyd]

Hi Yasser,

I think you need to explain more how you want segment the IBSR (Internet 
Brain Segmentation Repository) data.
Do you want to use gradient information or do you want to enhance the 
images? I don't really understand what your question is.
I'll try and give an answer anyway.

You can read about the Smoothing filters in chapter "6.7.1 Blurring" of 
the ITK Software guide. There are several examples with code in the 
directory "InsightToolkit-2.0.1/Examples/Filtering/".
If you want to calculate the gradient, maybe you want do some smoothing. 
You can do this by first smoothing the image and then calculating the 
gradient or you can directly convolve the image with a derivative of a 
gaussian (e.g. itkRecursiveGaussianImageFilter 
<http://www.itk.org/Doxygen/html/classitk_1_1RecursiveGaussianImageFilter.html>).

Chapter "6.7.3 Edge preserving Smoothing" describes the edge preserving 
smoothing operations, such as anisotropic diffusion. This will smooth 
the areas with small gradient and preserve or enhance the area with high 
gradient (i.e. the edges).

-
Bryn


>Hi all,
>i am using IBSR data to segment the brain tumor is the
>Gaussian filter is a good choice for smoothing these
>image while it blurring the edges? or i *must* use any
>edge preserving filter?
>thanks
>yasser
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