[Insight-users] select more than one seeds when I use itkfastmarchingimagefilter?

[Ivan Macia]

Hi Xujf,

As Luis says, setting several seed points you will have several fronts
propagating at the same time. As the time the front needs to visit a pixel
in the region to segment is proportional to the distance of that pixel to
the closest seed point, setting several seed points you have these
advantages (providing the seed points are placed approximately along the
skeleton of you object as Luis states):

a) You will have more chances of not missing some parts in your object.
b) The segmentation process will be faster as the time needed to visit the
whole object is reduced.
c) You will have less risks of leaks in regions already visited because the
fronts stop propagating earlier (you can set a smaller value for the
Stopping Value parameter).

You can see the effects of setting several seed points by choosing
increasing values for the Stopping Value parameter to see the evolution of
the fronts.

Hope this helps

Iv¨¢n

> -----Mensaje original-----
> De: insight-users-admin at itk.org
> [mailto:insight-users-admin at itk.org]En nombre de Luis Ibanez
> Enviado el: jueves, 22 de abril de 2004 19:27
> Para: xujf at sjtu.edu.cn
> CC: insight-users at itk.org
> Asunto: Re: [Insight-users] select more than one seeds when I
> use itkfastmarchingimagefilter?
>
>
>
> Hi Xujf,
>
> Yes, you can set more than one seed in itk::FastMarchingImageFilter.
>
> http://www.itk.org/Insight/Doxygen/html/classitk_1_1FastMarchi
> ngImageFilter.html
>
> Note that the SetTrialPoints() method is receiving a
> NodeContainer class.
> This class is designed for holding *many* seed points.
>
> What changes in the execution of the filter is that fronts are now
> developed from
> all the seed points simultaneously.
>
> It is very useful to provide multiple seed points, specially
> for objects
> with
> non-convex shapes. If you think of the object shape in terms of its
> skeleton,
> you should put seed points at least in all the nodes of the skeleton.
>
> You may want to play with the implementation of the
> FastMarching filter
> as a plugin in VolView. You can place any number of 3D markers as seed
> points and then run the filter. If you find that sections of
> your object are
> missing, you can easily undo the filter add more seed points
> and re-execute.
>
> The source code for VolView plugins is available at
>
> InsightApplications/VolviewPlugins
>
>
> Regards,
>
>
> Luis
>
>
> ----------------
> xujf wrote:
>
> >Hi,all:
> >
> >  I have a question:whether I can select more than one seeds
> when I use itkfastmarchingimagefilter
> >to segment a 3D image. If I can select more than one seeds.
> what is the difference of segmentation process
> >between the method which I  select only seed and the one I
> select more than one seeds.
> >
> >Thanks in advance!
> >xujf
> >
> >
>
>
>
>
>