[Insight-users] Re: gray scale erosion
Luis Ibanez
luis.ibanez at kitware.com
Mon Aug 2 23:46:07 EDT 2004
Hi Raghu,
Yes, if your pixel spacing is 0.125mm and you select
and structuring element of radius = 4 pixels then
your structure will be eroded by 2mm.
Note that this is just an approximation since your
strucutre is a digital one, and therefore distances
can not be measured in the classical sense.
If you really have some precision concerns, you should
use the DanielsonDistanceMapImage filter. Compute a
distance map to the complement of your object and then
threshold that map at 2 millimeters.
Regards,
Luis
----------------------------
raghu venkatram wrote:
> Luis,
>
> Sorry if I did not state my question properly,
>
> I understand that the radius of the structuring element is specified in
> number of pixels as opposed to physical coordinates.
>
> My question is that I wanted a shrinkage of 2mm on isotropic data, would
> a structuring element of radius of 4 help me acheive this? My pixels are
> .125 mm in x y z, (256, 256, 237)
>
> Thanks,
>
> Raghu
>
> >From: Luis Ibanez <luis.ibanez at kitware.com>
> >To: raghu venkatram <raghu_420 at hotmail.com>
> >CC: Insight-users at itk.org
> >Subject: [Insight-users] Re: gray scale erosion
> >Date: Mon, 02 Aug 2004 15:55:26 -0400
> >
> >
> >Hi Raghu,
> >
> >Mathematical Morphology filters in ITK do not use
> >physical coordinates but pixel coordinates. The
> >radius of the structuring element is specified
> >in number of pixels.
> >
> >This is traditional in Mathematical Morphology, and
> >should invite some reflexion on your part before
> >you apply such filters to any anisotropic data....
> >
> >
> > Regards,
> >
> >
> > Luis
> >
> >
> >------------------------------
> >
> >raghu venkatram wrote:
> >
> >>hello all,
> >>
> >>I am using the mathematical morphology gray scale erosion filter to
> >>shrink some volume of interest.
> >>
> >>My pixels are isotrpic in x, y and z and are .125 mm. I was not
> >>sure if in ITK the radius of the structuring element would let me
> >>specify the amount of shrinking in x, y z, i would like 2mm in all
> >>3 dimensions.
> >>
> >>
> >>
> >>Thanks, in advance
> >>
> >>Raghu
> >>
> >>
> >>
> >>
> >>
> >> >From: Luis Ibanez <luis.ibanez at kitware.com>
> >> >To: raghu venkatram <raghu_420 at hotmail.com>
> >> >CC: Insight-users at itk.org
> >> >Subject: Re: [Insight-users] landmark initialized mutual
> >>informationregistration
> >> >Date: Tue, 27 Jul 2004 17:47:29 -0400
> >> >
> >> >
> >> >Hi Raghu,
> >> >
> >> >What version of ITK are you using ?
> >> >
> >> >There was a bug fixed recently in this application,
> >> >related to the number of parameters used in some
> >> >Transforms.
> >> >
> >> >If you want to use this application, you probably
> >> >want to use the CVS version.
> >> >
> >> >
> >> > Regards,
> >> >
> >> >
> >> > Luis
> >> >
> >> >
> >> >
> >> >--------------------------
> >> >raghu venkatram wrote:
> >> >
> >> >>
> >> >>Hi All,
> >> >>
> >> >>I am running the land mark initialized mutual information based
> >> >>registration application.
> >> >>I am trying to register an MR and a CT volume,
> >> >>
> >> >>MR volume: 256x256x74 (.89844 mm x .89844 x 2mm)
> >> >>CT volume: 512 x 512x55 ( ..55469 x .55469 x 2mm) voxel sizes
> >> >>
> >> >>I get some strange runtime errors, while initializing with 4
> >> >>landmark points.
> >> >>below is the log with osme of my debugging echo statements. I
> >>also
> >> >>get a Debug error MS VC++ error: Damage: after normal block
> >>#7071.
> >> >>
> >> >>I would be glad if somebody could give me some pointers or had
> >> >>similar experiences.
> >> >>
> >> >>Thanks,
> >> >>Raghu
> >> >>
> >> >>Registration begins.
> >> >>Register using landmarks
> >> >>fixed landmarks=4
> >> >>moving landmarks=4
> >> >>68.2813 105.117 72
> >> >>111.406 63.7891 72
> >> >>143.75 110.508 72
> >> >>108.711 148.242 72
> >> >>141.445 155.867 43.8203
> >> >>115.375 127.023 43.8203
> >> >>0 0 0
> >> >>171.953 128.688 43.8203
> >> >>centers
> >> >>428.773 411.578 131.461
> >> >>432.148 427.656 288
> >> >>centers
> >> >>107.193 102.895 32.8652
> >> >>108.037 106.914 72
> >> >>0 0 0
> >> >>LandmarkRegistrator: InitialParameters =
> >> >>[0, 0, 0, 107.193, 102.895, 32.8652]
> >> >>-------------------------------------------------
> >> >>Exception caught in LandmarkRegistrator:
> >> >>unknown exception caught !!!
> >> >>-------------------------------------------------
> >> >>-------------------------------------------------
> >> >>Exception caught in ImageRegistrationApp:
> >> >>unknown exception caught !!!
> >> >>-------------------------------------------------
> >> >>DEBUG: Landmark registration FINAL centered versor transform:
> >> >>[0, 0, 0, 0, 0, 0]
> >> >>DEBUG: Landmark registration FINAL affine transform:
> >> >>[1, 0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0]
> >> >>
> >>
> >> >>_________________________________________________________________
> >> >
> >> >
> >> >
> >> >
> >> >_______________________________________________
> >> >Insight-users mailing list
> >> >Insight-users at itk.org
> >> >http://www.itk.org/mailman/listinfo/insight-users
> >>
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> >
> >
> >
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