[Insight-users] Pipeline question

[Paul Yushkevich]

Hi,

I have a small question about the pipeline.

I have a large image that is the input to three slice extraction filters 
that operate on different regions of the image.  Now, every time I call 
Update() on the outputs of these filters, the entire pipeline gets 
rerun, even though neither the input image nor the parameters of the 
filters had changed.

I traced this down to the fact that the input image is Modified() every 
time its requested region  changes.  As different RequestedRegions are 
propagated from the three different filters, the input image's MTime 
gets incremented, and the image appears as if it has changed, even 
though it really hadn't.

Is there any way around this issue?  I want to be able to call Update() 
frequently on the outputs of the three slice filters, but only have the 
filters run if the image or the filter parameters have changed.

Paul

-- 
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Paul A. Yushkevich, Ph.D.
President, Cognitica Corporation

17 Flemington Rd
Chapel Hill, NC 27517
Tel: 1-919-929-7652
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