[Insight-developers] FloodFilledSpatialFunctionIterator

[Miller, James V (CRD)]

Damion,

The idea here is that these filters and your iterators share a common "technique".  Perhaps these
filters and your iterators could both use some the same helper class (or more likely these filters
would use something derived from a helper class and your iterator would probably inherit from this
helper class).  It might even be possible for your iterator to be used directly by these algorithms.

On an implementation note: I would avoid keeping a link list of the indices to visit (you mentioned
having operator++ move through this list).  That would be extremely memory intensive.  I would
suggest encapsulating operator++ algorithmetically. So, operator++ performs one step in the flood
fill algorithm to determine the next index.

Jim


-----Original Message-----
From: Damion Shelton [mailto:dmsst59+@pitt.edu]
Sent: Tuesday, June 05, 2001 3:06 PM
To: vikram@insightful.com; 'insight-Developers'
Subject: Re: [Insight-developers] FloodFilledSpatialFunctionIterator


Hi...

> This FloodFill concept seems very similar to the Fast Marching algorithm
> and also the Fuzzy Connectedness algorithm. Both of these algorithms rely
on
> starting from one or more seed points and marching outward while computing
> some spatial function.

Hmmm.... I think I can see similarities between the routines, but I'm not
sure that refactoring would be worthwhile - I assume by refactorize you mean
creating a base or friend class that embodies the idea of proceeding outward
from a seed?

A potential difficulty, I think, is that FloodFilledSpatialFunctionIterator
behaves externally as an iterator while the Fast Marching and Fuzzy
Connectedness are both Image Filters. I don't suppose this is a huge
distinction, but the only common element would be the fill routine, which is
pretty trivial (at least in my implementation). Implementing a general "walk
out from a seed" routine might end up being more complicated than using our
individual implementations.

I'll check-in FloodFilledSpatialFunctionIterator in the next couple of days,
and you can let me know what you think.

-Damion-


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