AW: [Insight-users] itkGrayscaleErodeImageFilter

salah salah at gris . uni-tuebingen . de
Thu, 5 Jun 2003 10:04:27 +0200


Hello James,

I actaully did not understand. The boundaries that I mean
are the margins of the image, i.e, the first and last n=20
pixels/slices in all directions, where n is the radius of=20
the structuring element. only these pixels/slices are filled
with zeros, the rest of the image is quite fine.

Thanks,
Zein



-----Urspr=FCngliche Nachricht-----
Von: Miller, James V (Research) [mailto:millerjv at crd . ge . com]
Gesendet: Mittwoch, 4. Juni 2003 18:56
An: salah; Itk (E-Mail)
Betreff: RE: [Insight-users] itkGrayscaleErodeImageFilter


I wasn't sure what boundary condition to use for these filters. =20
I think it currently uses a constant value for pixels outside the
boundary of the image (with the constant set to zero). So the=20
erosion would result in zeros propagating into the image.  The
boundary condition could be changed to the ZeroFluxNeumann boundary
condition if that makes more sense.

Jim



-----Original Message-----
From: salah [mailto:salah at gris . uni-tuebingen . de]
Sent: Wednesday, June 04, 2003 9:45 AM
To: Itk (E-Mail)
Subject: [Insight-users] itkGrayscaleErodeImageFilter


Hi all,

I have used the itkGrayscaleErodeImageFilter. I notived that
it does not erode the boundary voxels. In other words, the=20
boundary of thickness=3D radius of the structuring element  is=20
simply replaced with 0's. I think the filter is not meant to do
so! right?=20
By the way, the itkGrayscaleFunctionErodeImageFilter does
not show this effect.
Note: i would be satisfied if the itkGrayscaleErodeImageFilter=20
does not touch the boundary voxels, i.e if it leaves then=20
unchanged, but replacing them with zero is an undesirable=20
effect (at least for me).=20

Could anybody please check if he/she get this effect with
these filters ?? Could it be a bug ??


Thanks,
Zein


->8<------------->8<------------->8<------------->8<------------->8<-----=
---
----->8<-
Zein I. Salah=20
University of Tubingen, WSI-GRIS, Sand 14, 72076 Tubingen=20
Email: salah at gris . uni-tuebingen . de
Tel.: (07071) 29 75465 (GRIS),           Fax: (07071) 29 54 66

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