[Insight-developers] periodic boundary condition

[Hans Johnson]

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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-- 
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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
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