[Insight-developers] periodic boundary condition

[Hans Johnson]

Josh,

Thanks for the clarification.  I am still having trouble determining when
each of the region types should be used.

Regards,
Hans

On Tue, 11 Feb 2003, Joshua Cates wrote:

> Hi Hans,
> 
> Yes, I agree you will want LargestPossibleRegion = BufferedRegion.  This
> can be handled automatically at the filter level by providing an
> implementation of GenerateInputRequestedRegion() which sets
> RequestedRegion = LargestPossibleRegion (see
> itkNeighborhoodOperatorImageFilter.txx, for example).
> 
> I believe wrapping around the BufferedRegion will be correct in this case. 
> 
> In general, it seems that any algorithm which uses a periodic boundary
> condition should require that RequestedRegion = LargestPossibleRegion.
> 
> 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 Tue, 11 Feb 2003, Hans Johnson wrote:
> 
> > Josh,
> > 
> > The need for periodic boundaries is most often needed to reconcile 
> > differences between spatial and frequency domain representations of an 
> > image.  I don't think it makes sense to wrap boundaries on the buffered 
> > region, you must wrap the boundaries on the entire image.
> > 
> > In particular, I am thinking of the case where the periodic boundaries 
> > are used on the output of a frequency domain (FFT) filter applied to an 
> > image.
> > 
> > Perhaps it is upto the application programmer to ensure that the 
> > BufferedRegion=LargestPossible region.
> > 
> > Regards,
> > Hans J. Johnson
> > hans-johnson@uiowa.edu
> > 
> > 
> > Joshua Cates wrote:
> > > Sorry, here is the complete message:
> > > 
> > > Hi,
> > > 
> > > I am writing a periodic boundary condition object for the neighborhood
> > > iterators.  This is class which returns out-of-bounds values
> > > by "wrapping around" the image.
> > > 
> > > I'm looking for opinions on the following issue.  A neighborhood iterator
> > > will only invoke the boundary condition if it finds itself touching an
> > > edge of the Image::BufferedRegion.  My inclination is to wrap around the 
> > > buffered region, regardless of the region over which the iterator was 
> > > initialized.  Is there any reason to wrap over the intialized region 
> > > instead?  Would it be useful to have the option to do both?
> > > 
> > > 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
> > > 
> > > 
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> > 
> > 
> > -- 
> > ===================================================================
> > Hans J. Johnson                              W294 GH
> > hans-johnson@uiowa.edu                       Dept. of Psychiatry
> > http://www.psychiatry.uiowa.edu/~hjohnson    The University of Iowa
> > (319) 353-8587                               Iowa City, IA 52242
> > ===================================================================
> > 
>