[Insight-developers] CurvatureAnisotropicDiffusionTest failin g

[Joshua Cates]

Yes, the default parameters should still be ok.

Josh.

______________________________
 Josh Cates			
 School of Computer Science	
 University of Utah
 Email: cates@sci.utah.edu
 Phone: (801) 587-7697
 URL:   http://www.sci.utah.edu/~cates


On Thu, 20 Mar 2003, Miller, James V (Research) wrote:

> Josh, 
> 
> Have the defaults been updated to "reasonable" values for the
> TimeStep?
> 
> 
> 
> > -----Original Message-----
> > From: Joshua Cates [mailto:cates@sci.utah.edu]
> > Sent: Thursday, March 20, 2003 1:01 PM
> > To: Luis Ibanez
> > Cc: Lorensen, William E (Research); Insight-developers (E-mail)
> > Subject: Re: [Insight-developers] CurvatureAnisotropicDiffusionTest
> > failing
> > 
> > 
> > Hi Bill and Luis,
> > 
> > Additionally, I made some adjustments yesterday to the 
> > CurvatureAD filter
> > which clamp the maximum timestep to guarantee stability.  I 
> > would suggest
> > generating a baseline image for the CurvatureAD filter using 
> > a time step
> > of 0.125 on the 2D image (0.0625 on 3D image).  Double those for the 
> > GradientAD filter.  In retrospect, exposing the time step to 
> > users was a 
> > dangerous idea.
> > 
> > I'll add more documentation to these filters to better 
> > explain the time 
> > step parameter.
> > 
> > Thanks,
> > 
> > Josh.
> > 
> > ______________________________
> >  Josh Cates			
> >  School of Computer Science	
> >  University of Utah
> >  Email: cates@sci.utah.edu
> >  Phone: (801) 587-7697
> >  URL:   http://www.sci.utah.edu/~cates
> > 
> > 
> > On Thu, 20 Mar 2003, Luis Ibanez wrote:
> > 
> > > Hi Bill,
> > > 
> > > It's great to have the regression testing working !
> > > 
> > > ---
> > > 
> > > Looking at the images,
> > > 
> > http://www.itk.org/Testing/Sites/starsend.kitware.com/WinXP-VC
> > 7/20030320-1144-Experimental/Results/__Examples_Filtering_Curv
> > atureAnisotropicDiffusionImageFilterTest.html
> > > 
> > > Here is what seems to happen,
> > > 
> > > Some day ago a glitch was found in the anisotropic diffusion
> > > filters that was preventing the TimeStep from being used.
> > > 
> > > That is, the User settings were not being honored. Instead,
> > > a default time step was always being used.  Josh rapidly
> > > fixed this bug, and as a consequence all the code that was
> > > using anisotropic filters suddenly started to actually use
> > > the TimeStep parameters. It happened that most of these settings
> > > were incorrectly tuned, often leading to numerical instabilities.
> > > 
> > > The Baselineimage for this filter seems to have been generated
> > > just after the bug was fixed but before the new parameters were
> > > tunned. The 'chekers'-like  appearance of the image is due to
> > > the numerical instabilities originated from too large values
> > > of the time step.
> > > 
> > > So, to summarize:
> > > 
> > >    Please update the Baseline image with the current one.
> > >    The smooth image appearing as "Testimage" is the right one.
> > > 
> > > 
> > > BTW, this may be happening with other tests...
> > > 
> > > 
> > >      Luis
> > > 
> > > 
> > > -----------------
> > > Lorensen, William E (Research) wrote:
> > > > Luis and Josh,
> > > > The subject regression test from Examples/Filtering is 
> > failing. I think the
> > > > changes Josh made yesterday to the filter have had an 
> > effect. Do you want me
> > > > check in a new baseline image or is there a problem?
> > > > 
> > > > 
> > http://public.kitware.com/Insight/Testing/HTML/TestingResults/
> Sites/coffee.k
> > >
> itware/Linux-gcc296/20030320-0500-Nightly/Results/__Examples_Filtering_Curva
> > > tureAnisotropicDiffusionImageFilterTest.html
> > > 
> > > Bill
> > > 
> > > _______________________________________________
> > > Insight-developers mailing list
> > > Insight-developers@public.kitware.com
> > > http://public.kitware.com/mailman/listinfo/insight-developers
> > > 
> > 
> > 
> > 
> 
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