[Insight-users] are itkConnectedComponentImageFilter and itkBinaryDilateImageFilter

[Gaëtan Lehmann]

Le 16 nov. 09 à 20:47, Baoyun Li a écrit :

> Dear Gaetan:
>
> Claiming structur element as [3 3 1] seems to be a simple solution.
>
> What I am wondering is how about if I only want to dilate or erod  
> one voxel with slice? How to give teh structure elements in this  
> case. Can I give structure elements as [1 1 0.33]?  Seem the way you  
> suggested has to do dilation with slice with 3 voxel.

[3, 3, 1] is the radius of the structuring element that you set with  
SetRadius(). The size of the structuring element element is the radius  
* 2 + 1 on each dimension. A kernel of radius [3, 3, 1] has a size [7,  
7, 3].

If you want to work on slices, you can use a radius of 0 on the last  
dimension - [3, 3, 0] for example.

Gaëtan

>
> Is that true:
> thanks
>
> Baoyun
>
> From: Gaëtan Lehmann <gaetan.lehmann at jouy.inra.fr>
> To: Baoyun Li <baoyun_li123 at yahoo.com>; Luis Ibanez <luis.ibanez at kitware.com 
> >
> Cc: ITK Users <insight-users at itk.org>
> Sent: Mon, November 16, 2009 9:20:19 AM
> Subject: Re: [Insight-users] are itkConnectedComponentImageFilter  
> and itkBinaryDilateImageFilter
>
>
> Hi,
>
> For BinaryDilateImageFilter, it is possible to take the spacing into  
> account when choosing the kernel size - the size on the third  
> dimension should be three time smaller than on the two other ones -  
> for example [3,3,1]. There is nothing to do for the  
> ConnectedComponentImageFilter.
>
> I'm not sure to understand how the spacing can have an impact on the  
> performance of those filters - by definition, they are working on  
> the neighbors of the pixels. Resampling the image shouldn't have  
> much effect on the result, but will certainly have a quite bad  
> effect on the execution time, and on the required memory!
>
> Gaëtan
>
>
> Le 15 nov. 09 à 16:48, Luis Ibanez a écrit :
>
> > Hi Baoyun,
> >
> > The two filters:
> >
> > * itk::ConnectedComponentImageFilter    and
> > * itk::BinaryDilateImageFilter
> >
> >
> > Operate in Voxel (pixel) space.
> >
> > They DO NOT take the image spacing into account.
> >
> >
> > You may want to resample you image off spacings:
> >
> >      0x6 x 0.6 x 2.5 mm
> >
> > into an isotropic image with spacing
> >
> >      0x x 0.6 x 0.6333
> >
> > (e.g. splitting Z slices into three).
> >
> > In this way, the operations of the Connectivity and Morphology
> > filters will be closer to the intuitive expectations.
> >
> >
> >      Regards,
> >
> >
> >          Luis
> >
> >
> > -----------------------
> > On Fri, Nov 13, 2009 at 2:38 PM, Baoyun Li  
> <baoyun_li123 at yahoo.com> wrote:
> >> Dear All:
> >>
> >> Can somebody tell me whetehr itkConnectedComponentImageFilter and
> >> itkBinaryDilateImageFilter are operated on the physical space or  
> voxel
> >> space.
> >> I have 0.6mmx0.6mmx2.5 mm ct data and want to do some  
> morphorlogical
> >> operation.
> >>
> >> I think the performance will be affected if the morphorlogical  
> operation is
> >> done on voxel space.
> >>
> >> So please guid me wheter those filters are operated on physical  
> space? If
> >> not, what should I do.
> >>
> >>
> >> Thanks
> >>
> >> Baoyun
> >>
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> >>
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> >
> > Visit other Kitware open-source projects at
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> >
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> >
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>
> --Gaëtan Lehmann
> Biologie du Développement et de la Reproduction
> INRA de Jouy-en-Josas (France)
> tel: +33 1 34 65 29 66    fax: 01 34 65 29 09
> http://voxel.jouy.inra.fr  http://www.itk.org
> http://www.mandriva.org  http://www.bepo.fr
>
>
>

-- 
Gaëtan Lehmann
Biologie du Développement et de la Reproduction
INRA de Jouy-en-Josas (France)
tel: +33 1 34 65 29 66    fax: 01 34 65 29 09
http://voxel.jouy.inra.fr  http://www.itk.org
http://www.mandriva.org  http://www.bepo.fr

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