[Insight-users] Segmentation Editor - pixel spacing

[dean.inglis@on.aibn.com]

Hi Josh,

also, since interpretation of WS results is generally slice by slice, where in-plane spacing is typically isotropic anyway, scaled spacing is not important.
However, the 3D vtk surface renderings could make use of the spacing information.  Perhaps this could
be added to the visualization pipeline sometime
later...

thanks for the clarification,
Dean


> 
> From: Joshua Cates <cates@sci.utah.edu>
> Date: 2002/11/22 Fri PM 07:58:54 GMT-05:00
> To: Dean Inglis <dean.inglis@on.aibn.com>
> CC: Insight Users <insight-users@public.kitware.com>
> Subject: Re: [Insight-users] Segmentation Editor - pixel spacing
> 
> Hi Dean,
> 
> The filters used in this demo (underscore the word "demo") application do
> not currently make use of pixel spacing.  To have the preprocessing
> stage--diffusion and gradient magnitude--take spacing into account, you
> will need to resample the input data so that it is isotropic.  (Note that
> the watershed algorithm itself does not take derivatives or make distance
> measurements on its input image.)
> 
> We do plan to modify some of the basic image processing filters (like
> anisotropic diffusion) so that they include the option to scale
> derivatives.  Scaling will be optional because there is disagreement about
> whether it is always appropriate.  For example, one could argue that noise
> introduced in the image domain should be removed in the image domain.
> 
> Hope this clarifies things.
> 
> Josh.
> ______________________________
>  Josh Cates			
>  School of Computer Science	
>  University of Utah
>  Email: cates@sci.utah.edu
>  Phone: (801) 587-7697
>  URL:   www.cs.utk.edu/~cates
> 
> 
> On Fri, 22 Nov 2002, Dean Inglis wrote:
> 
> > Hi,
> > 
> > while experimenting wth the Segmentation Editor
> > app, I noticed that there appears to be no way 
> > to enter information about the spacing/dimensions
> > of pixels/voxels.  Is this intended and if so, why?
> > 
> > Dean
> > 
> > quote from Insight/Examples/Image/Image4.cxx :
> > " Medical images lacking 
> > // spatial information should not be used for purposes like medical
> > // diagnosis, image analysis, feature extraction, assisted radiation
> > // therapy or image guided surgery. In other words, medical images
> > // lacking spacing are not only useless but rather hazardous."
> > 
> > 
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> 
>