[Insight-users] Local Image Filter (adaptative threshold)

[Luis Ibanez]

Hi Mathieu,

I'm affraid we don't have such a filter.
However, it may be relatively easy to
implement (an probably add to the toolkit).

If you take a look at both the ConfidenceConnected
and the Threshold connected you will see that
most of the complexity is managed by the conditional
flood fill iterator.

The task left to the filter is basically to define
the boolean criterion for accepting new points.

--

Would you like to give it a try to implement your
suggested filter ?

Whar are exactly the local rule you would like
to see in the filter ?  e.g. a piece of pseudo-code
could help here.

Updating the seed point is also possible at each
iteration, it will be just a matter of defining
a rule for selecting the new seed (or set of seeds
since the FloodFill iterator accepts now a set
of them). What rule do you have in mind ?

We look forward to implement variants of the
ConfidenceConnected and ThresholdConnected filters
given that they have proved to be quite efficient.

On the other hand, you may want to take a look
at the adaptive enhancement filter used for
mamograms. This is a contrast enhancement filter
based on local properties. I wonder if you could
use it as a preprocessing step, just before using
one of the connectedness filters. Here is the man
page for the Plahe filter.
http://www.itk.org/Doxygen/html/classitk_1_1PlaheImageFilter.html


Please let us know what you think,


    Thanks


      Luis


-------------------------

Mathieu Malaterre wrote:
> Hi all,
> 
>   I am looking for an image filter that can threshold my image. It 
> should be a kind of mixture of ConnectedThresholdImageFilter but with 
> Local features. The filter would work on neightbourhood and not on a 
> global threshold. By the way I thought first that this filter would be 
> NeighborhoodConnectedImageFilter but there is only two *global* thresholds.
> 
>   What I would like is filter that would update the threshold while the 
> region grows. If it possible could you point me out some filters I could 
> use.
> 
>   I also notice the filter ConfidenceConnectedImageFilter but I would 
> like to update the seed point (not a fixed one) while the region grows.
> 
> Thanks,
> mathieu
> 
> 
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