[Insight-users] threshold parameter in watersehd segmentation

[Luis Ibanez]

Hi Juliette,

The Threshold parameter of the watershed filter is expected to be a
number in the range of values of the input image intensities.

This parameters will be used to define the "smallest" intensity change
in the image that will be considered as a water basin. Usually you want
to make this parameter something in the order of 1/100 or 1/1000 of the
water level (this is just a guideline, not a clear cut rule).

If you set the threshold value too low, then the filter will spend a lot
of time processing very small details of the image, that you not
actually care about. Note that if your image has a high level of noise,
you may want to run a smoothing filter on it, before you pass it to the
watershed segmentation filter.



    Regards,


       Luis


--------------------
Juliette Deniau wrote:
> Hi all,
> Could any one explain me the meaning of the threshold parameter in 
> watersehdImageFilter?
> I've read the SoftwareGuide and I've understand that this parameter is 
> used to generate the initial segmentation via the steepest descent 
> stategy.  its used to remove shallow background regions...but I couldn't 
> understand its a threshold of what?
> Thank you
> Juliette
>  
> 
> 
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