[Insight-users] Watershed segmentation -- how to access the detailed results?

[Atwood, Robert C]

Thanks for the info; it sounds like it may be easier to post process the
resulting image at least in the short run ..

Another question about this, using the results as they are, is there
already a list of the number of voxels contained in each region ? i.e.
How big is each differently 'coloured' region in the 3-d image? Or
should I go through and count them afterwards ?

Thanks again,


Robert


-----Original Message-----
From: Joshua Cates [mailto:cates at sci.utah.edu]=20
Sent: 01 April 2004 18:57
To: Atwood, Robert C
Cc: insight-users at itk.org
Subject: Re: [Insight-users] Watershed segmentation -- how to access the
detailed results?


Hi,

The short answer is no.  It's true that neighbor information is required

for the algorithm, but neighbors are only explicitly calculated after
the=20
initial segmentation (before the hierarchy of merges is computed).  You=20
probably want the neighbors of your final (merged) region, which are not

explicitly stored anywhere. =20

The data you need to compute neighbors is buried in the ivars of the
itkWatershedImageFilter, however, you'd have to pull it out and write a
separate algorithm.  Briefly, the data is the itkWatershedSegmentTable
contained in the itkWatershedSegmenter filter (a member variable of
itkWatershedImageFilter) and the itkWatershedSegmentTree accessible
through itkWatershedImageFilter::GetOutputSegmentTree.

Josh.

On Thu, 1 Apr 2004, Atwood, Robert C wrote:

>=20
> Once an image has been processed by the watershed filter, is there=20
> already a list of the regions and how many voxels are in each one? or=20
> even which regions neigbour upon which other regions? It seems that=20
> this information must be generated at some point during the watershed=20
> filter .. If so, how can this list be accessed?
>=20
> (Instead of iterating through the resulting image array and counting ,

> and locating adjoining regions, etc.)
>=20
> Thanks,
> Robert
>=20
> _______________________________________________
> Insight-users mailing list
> Insight-users at itk.org=20
> http://www.itk.org/mailman/listinfo/insight-users
>=20