[Insight-users] Apply filter only on a specific region ?

[Iván Macía]

Hi Luis,

Just a question. We were discussing here at work the meaning of the
different regions (Largest vs Requested vs Buffered). One question we had is
if you can process a part of the image only by setting the Requested Region
on the output, which seems quite straightforward and compatible with the ITK
pipeline definition. What would you get here? An image whose Largest
Possible Region is the same as the one you requested?

The idea I have is that the Requested Region is an important part of the ITK
pipeline and is used by the filters, at least internally, so why is its use
discouraged in this case?

Thanks in advance

Iván

PD: it is common the case in which we have to process only a certain part of
the image in medical applications, for example when we have to calculate
statistics in a region of interest from a 3D image, as defined by the
radiologist. It may be inconsistent from the point of view image processing
but it works :) This is just an example but we have find many cases in which
we have had to restrict ourselves only to a certain part of the image as
defined by the user, due to memory limitations or for a faster processing
among other reasons.


-----Mensaje original-----
De: insight-users-bounces at itk.org [mailto:insight-users-bounces at itk.org] En
nombre de Luis Ibanez
Enviado el: domingo, 24 de enero de 2010 16:11
Para: dsdfdff sfdsf
CC: insight-users at itk.org
Asunto: Re: [Insight-users] Apply filter only on a specific region ?

Hi Steve,

It depends....

What exactly do you want at the output ?

A) The full input input with the subregion modified ?

or

B) only the modified subregion ?

---

If you want (A) you will have to use a pipeline
such as:

RegionOfInterestImageFilter
MedianImageFilter
PasteImageFilter

If you want (B) you could use simply


RegionOfInterestImageFilter
MedianImageFilter

or even use the SetRequrestedRegion()
of the Median filter directly.  Although
this last option is not a recommended
practice, unless you are very familiar
with the inner-workings of the ITK pipeline.


--

On a side note:

Why do you want to do such thing ?    :-)