[Insight-users] offset of a curve using level sets

[Juan Cardelino]

Dear Dawood,
                   Thanks for the tip. All these solutions seems fine but
overcomplicated. I think I would go with the fast marching solution.
Thanks for your time.
Best regards,
                  Juan

On Thu, Feb 3, 2011 at 9:44 PM, Dawood Masslawi <masslawi at gmail.com>wrote:

> Dear Juan,
>
>
> Level set segmentation filers have a reverse expansion flag which
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> can be turned off or on for changing the direction of the surface
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> expansion. You can change the direction of the expansion after n
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> iterations and go in the reverse direction for m iterations and
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> maximum number of iterations needed for both steps would be n+m.
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> n indicates the number of iterations needed for reaching the
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> optimal level set and m is the number of iterations needed for
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> inflating or deflating the surface.
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> Hope this
>  helps,
>
>
> Dawood
>
>
> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
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> >>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
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> >>* On Thu, Feb 3, 2011 at 12:05 PM, Juan Cardelino*
> >>* <juan.cardelino at gmail.com <http://www.itk.org/mailman/listinfo/insight-users>> wrote:*>>>* I want to perform a very simple task: I have a curve represented as*>>>* the level set of an implicit function (coming from a level set*>>>* segmentation algorithm) and I want to inflate (or deflate) it a*>>>* certain amoun. Lets say 10 pixels from the original location. As I'm*>>>* used to work with full level sets, I usually substract 10 pixels from*>>>* the implicit function. For that you need the full implicit function.*>>>* As in ITK we use only a band near the level set, that won't work for*>>>* sure.*>>>* All the alternatives I'm thinking seem to be somehow complicated:*>>>**>>>* 1) compute the zero contour and use fastmarching (signed) on the it,*>>>* then cut  this distance function at the desired level.*>>>* 2) evolve the level set function with a constant curvature dependent*>>>* speed, until it advances the desired amount of pixels*>>>**>>>* I'm just wondering if there is anything already built in ITK.*>>>* Thanks in advance.*>>>* Regards,*>>>*       Juan*
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