[Insight-developers] Re: Recursive Gaussian : & Scale Space

[Luis Ibanez]

Hi Gunnar,


 > Interestingly enough this example sets normalization across scale to
 > false.


mm, how ironic    :-)


Thanks for pointing this out.
We just committed a fix for this mistake.

You may find interesting to run it on a simple
image. For example on

     Insight/Examples/Data/Circle.png


a command line like

     ScaleSpaceGenerator2D   Circle.png   CicleScaleSpace


will generate a series of 2D metaimages containing
the 3D scale space.



     Regards,



         Luis



------------------------------
Gunnar Farneback wrote:

>>1) Yes, I agree with you in that this normalization is image dependent.
>>    The test is usually done with an input image that has a single pixel
>>    On, which is the equivalent of a discrete Dirac Delta.
> 
> 
> Ok, with that restriction the test makes sense. I'm more doubtful
> about the usefulness of having normalization for an impulse, however.
> 
> 
>>3) Yes, please look at the example:
>>
>>            Insight/Examples/Filtering/
>>                     ScaleSpaceGenerator2D.cxx
>>
>>
>>    This example takes a 2D image as input and produces its
>>    ScaleSpace image, which is a 3D image, where "scale" is
>>    the 3rd coordinate.  Scale space analysis usually involves
>>    to track isosurfaces of the 3D image in order to identify
>>    image features that are stable across scale.
>>
>>    An interesting exercise is to generate the 3D ScaleSpace
>>    of a 2D image, then load it in to ParaView, VolView or
>>    Slicer and generate isosurfaces on the scale.
> 
> 
> Interestingly enough this example sets normalization across scale to
> false.
> 
> /Gunnar
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