[Insight-users] Question about pipeline with Geodesic Active Contour

[OnezerO]

Hello Luis,
Thanks for the answer, I refer to the examples of the guide but i dont
totally understand the concepts, this in part because i dont dominate the
english language very well, that's why i'm posting here, i hope you can help
me with the next questions

1.-
>The GeodesicActiveContours doesn't really need you to provide a level set
that has been initialized with a
>distance function. You can pass directly your binary image as the input
LevelSet. 
So what's the use of the fastmarching method to calculate a distance map? in
the original pipeline?

2.-
When you say "speed image" you mean the "potential edge image"?

3.-
In the process of obtain the distance map is more apropiated to use
Danielsson or SignedDanielsson?


Thanks in advantage

-----Mensaje original-----
De: Luis Ibanez [mailto:luis.ibanez at kitware.com] 
Enviado el: Martes, 25 de Octubre de 2005 0:00
Para: OnezerO
CC: insight-users at itk.org
Asunto: Re: [Insight-users] Question about pipeline with Geodesic Active
Contour

Hi Onezero,

The GeodesicActiveContours doesn't really need you to provide a level set
that has been initialized with a distance function.
You can pass directly your binary image as the input LevelSet.

The speed image seems to be ok, if you are building it by taking the Sigmoid
of the Gradient magnitude.

Please refer to the multiple examples on LevelSets in the ITK Software Guide

           http://www.itk.org/ItkSoftwareGuide.pdf

You will find them in the "Segmentation" chapter.


A descriptioin of what a Distance Map is, can also be found in the ITK
Software Guide.  Please not that you don't need to compute a Distance map
for this particular Level Set filter.


    Regards,


       Luis



---------------
OnezerO wrote:
> Hello,
> Please, first i need to know if this pipeline made for segmentation 
> it's theoricly correct
>  
>                        
> -->CurvatureAnisotropicDiffusionImageFilter-->GradientMagnitudeRecursi
> veGaussianImageFilter-->SigmoidImageFilter
>                        
> |

> |
> Original
> Image--|

> |
>                        |

> |
>                        
> -->BinaryThresholdImageFilter-->SignedDanielssonDistanceMapImageFilter
> -->DistanceMapImage---------GeodesicActiveContourLevelSetImageFilter
>

> |
>
BinaryThresholdImageFilter
>
|
>

> SegmentationImage
>  
>  
> as a second question i want to know what is a Distance Map and how to 
> "read it", and finally i'm using the methos InsideIsPositiveOn () in 
> the signeddanielsson what's the functionality of this method? is well 
> used in the pipeline
>  
> Any Comments please
>  
> Thanks
>

> 
> 
> 
> ----------------------------------------------------------------------
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> 
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