[Insight-users] Scalar Speed Image in Level Set Approaches

[Luis Ibanez]

Hi Diana,

You have (at least) two options:

1) Use the Advection field term in the Geodesic Active Contours.
    Normally, the vector field that represents the advection term
    will help to push back the level set when it goes too far from
    the border (... as long as there is actually a border there...)

2) You can have negative speed terms, but that may require that you
    retouch (e.g. derive and overload some methods) from the level set
    function.

    You may want to look at how this is done in the
    ThresholdSegmentationLevelSetFunction


  Please let us know if you have further questions,


      Thanks


         Luis


--------------------------------
droettger at uni-koblenz.de wrote:
> Hey,
> 
> I'm testing ITK level set approaches in my segmentation framework and want
> the front to shrink, when it crosses over boundaries.
> Is it possible to manipulate the scalar speed image to be negative in some
> cases, for example at some specific intensity values, on my own and pass
> positive as well as negative values in the speed image to the level set
> algorithm?
> 
> Is it possible in all level set methods, for example
> ShapeDetectionLevelSetImageFilter or
> GeodesicActiveContourLevelSetImageFilter?
> 
> Thanks!
> Best regards,
> Diana
> 
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