[Insight-users] neighborhood of a neighborhood

[Joshua Cates]

Depending on how large your larger neighborhood is, you might not want to
pay the overhead of maintaining the outer neighborhood iterator.  In that 
case just use a regular iterator to keep track of the index and redefine 
smallRegion at each outer iteration.

Josh.

On Wed, 27 Aug 2003, Miller, James V (Research) wrote:

> This may be the same as Josh suggested:
> 
> The key here is that an iterator walks a prescribed region. So use two 
> neighborhood iterators.  The first walks the full region of interest and 
> has a large radius.  As the first iteration moves, you define a region off
> this iterator (convert its location and radius to an start index and size 
> for a region, start index = location - radius, size = 2*radius+1).  Define
> a second iterator that walks this newly defined region.
> 
>     outer_iter = NeighborhoodIteratorType(largeRadius,
>                                       this->GetInput(), largeRegion);
>     while ( !outer_iter.IsAtEnd() )
>       {
>       // these next two lines probably won't compile, but you get the idea.
>       smallRegion.SetIndex( outer_iter.GetLocation() - 2 * largeRadius );
>       smallRegion.SetSize( 2 * largeRadius + 1 );
> 
> 	inner_iter = NeighborhoodIterator(smallRadius, this->GetInput(),
> smallRegion);	 
> 
>       while ( !inner_iter.IsAtEnd() )
>         {
> 	  // do something
> 
>         ++inner_iter;
>         }	    
> 
>       ++outer_iter;
>       }
> 
> 
> > -----Original Message-----
> > From: Joshua Cates [mailto:cates at sci . utah . edu]
> > Sent: Wednesday, August 27, 2003 1:21 PM
> > To: John M. Galeotti
> > Cc: insight-developers at itk . org; insight-users at itk . org
> > Subject: Re: [Insight-users] neighborhood of a neighborhood
> > 
> > 
> > Hi John
> > 
> > One way to do this would be to define a region R and a neighborhood 
> > iterator N on R.  You would have to "manually" iterate R through the 
> > image by incrementing its Index and modifying the Size.  You 
> > could grab 
> > the Index from a regular iterator moving through the image.
> > 
> > Josh.
> > 
> > On Tue, 26 Aug 2003, John M. Galeotti wrote:
> > 
> > > Is it possible to iterate a small neighborhood through a large 
> > > neighborhood which is itself iterating through a much larger image?
> > > 
> > > John Galeotti
> > > jgaleotti at cmu . edu
> > > 
> > > _______________________________________________
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> > > Insight-users at itk . org
> > > http://www . itk . org/mailman/listinfo/insight-users
> > > 
> > 
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>