[Insight-users] Which filter does the 3D volume shrinking?

[Luis Ibanez]

Hi Ashish,

You are right,

The MultiResolutionPyramidImageFilter
http://www.itk.org/Insight/Doxygen/html/classitk_1_1MultiResolutionPyramidImageFilter.html
can also be used for Shrinking an image.

Note however that the main purpose of this filter is to
prepare images for the MultiResolution registration framework.

There is a significant amount of overhead in this filter if you
use it only for Shrinking an image. The Pyramid filter performs
a sequences of Gaussian smoothing operations followed by
subsampling with the ResampleImageFilter.

The Gaussian smoothing is preventing aliasing effects during the
resampling process. You may or may not need this smoothing depending
on the content of spatial frequencies in the image.

If the purpose of the shrinking is just to have one subsampled
image, the Pyramid filter may be an overkill. But if the purpose
is to prepare a series of images for multi-resolution registration,
then the pyramid filter is a good way to go.



    Regards,



       Luis



---------------------------
Ashish Poddar wrote:
> pyramid filter can also be used for this purpose i think !
> 
> regards,
> Ashish.
> 
> On Mar 30, 2005 1:13 PM, Luis Ibanez <luis.ibanez at kitware.com> wrote:
> 
>>Hi George,
>>
>>The filter that does Shrinking is of course the "Shrink" filter :-)
>>
>>http://www.itk.org/Insight/Doxygen/html/classitk_1_1ShrinkImageFilter.html
>>
>>There is a non-threaded version of it too:
>>http://www.itk.org/Insight/Doxygen/html/classitk_1_1NonThreadedShrinkImageFilter.html
>>
>>If you are doing this for multiresolution Image registraion,
>>it is more formal to use the ResampleImageFilter according
>>to the instructions of the ITK Software Guide. The Resample
>>filter give you a more detailed control of the resampling
>>parameters, while the shrink filter simply takes integer
>>factors and samples the input image.
>>
>>   Regards,
>>
>>      Luis
>>
>>----------------------------
>>Li, George (NIH/NCI) wrote:
>>
>>
>>>Hi, Luis and all itk users:
>>>
>>>I am pretty sure that there is a filter that can shrink
>>>The size of the image volume with a desired, pre-defined
>>>range. But which one is it? Can anyone help me out here?
>>>
>>>Thanks,
>>>
>>>George
>>>_______________________________________________
>>>Insight-users mailing list
>>>Insight-users at itk.org
>>>http://www.itk.org/mailman/listinfo/insight-users
>>>
>>>
>>
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> 
> 
>