[Insight-users] More on: Can metrics handle nodata/void data values ?

[Carolyn Johnston]

Hi Luis,

I'm looking at doing the modification in the short term.

> Option (C) could be implemented using SpatialObjects.
> The big difference here is that the registration will
> be then performed between two SpatialObjects that
> each one encapsulate an image (fixed and moving images
> respectively). 

I am not completely  clear on what you mean by this... Is it necessary 
to modify the registration code so that SpatialObjects are used 
throughout, instead of images?

I was trying to design my changes so that I affect ITK code to the least 
extent possible, and do most of it through extending classes. If you 
want this functionality in ITK, however, maybe I shouldn't worry about 
that. 

> I still would be inclined to do the modifications on
> the metrics themselves, rather than the iterators.
> Making the change in the iterator simply hides the
> "if" deeper into the code. 

OK, I agree with this. I also wanted to avoid duplicating code in the 
subclasses of ImageToImageMetric. I don't see any way around that though.

-- 
Carolyn P. Johnston, Ph.D.
Sr. Research Engineer
Vexcel Corporation