[Insight-users] RequestedRegion vs RegionOfInterestImageFilter

[Mathias Seitel]

Hello all,

I'm currently looking for a way to force any image filter not to use the 
whole of it's input image, but only a user-defined portion of it. So far 
I understood that the RequestedRegion of an image could be used or this 
purpose but I just found that this approach doesn't work in all cases, 
e.g. the ConnectedThresholdImageFilter automatically sets the 
RequestedRegion to its LargestPossibleRegion. Am I right?

What I now have in mind is to interpose an ExtractImageFilter or an 
RegionOfInterestImageFilter between the concerned image and the filter. 
One obvious drawback here is the additional memory consumption. Is it 
possible to preserve any specified RequestedRegion, or is there some 
other way to address the above problem? Btw. the reason why I want to 
implement this is to have a simple way to limit a segmentation 
algorithm, e.g. region growing, to a strict area.

Thanks,
Mathias