[Insight-users] EDM Danielsson filter

[Luis Ibanez]

Hi Radhika,

The implementation of the Danielsson distance in ITK
only compute distances from the "object". Pixels inside
the object gete assigned distance values == 0.

As you suggested, the way of obtaining a signed distance
from the object edge is to feed the filter twice, once
with the image, and then with the image inverted.

This issue has been entered as a Feature Request in
the bug tracker. You will find it under Bug # 737:

http://www.itk.org/Bug/bug.php?op=show&bugid=737&pos=0


Note that you can also generate a signed distance map
using the Reinitialize filter on the LeveSet framework:
http://www.itk.org/Insight/Doxygen/html/classitk_1_1ReinitializeLevelSetImageFilter.html



Regards,


    Luis



--------------------------------
Radhika Sivaramakrishna wrote:
> Hi,
> 
> I am a little confused by the operation of the Danielsson filter. My 
> understanding of EDM was that at every pixel, I would have the distance 
> from the nearest background pixel.
> 
>  
> 
> Also, for pixels within an object, what distances would be returned? I 
> would like distances to the nearest background pixel, so that I can use 
> this information for postprocessing.
> 
> Is the way it is implemented opposite of that? Does this mean that for 
> pixels that are part of an object, distance is essentially written out 
> as zero?
> 
>  
> 
> Is a simple way to correct that, to just invert the image and then pass 
> it to the filter?
> 
>  
> 
>  
> 
> Thanks
> 
> Radhika
> 
>  
> 
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