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

[Dawood Masslawi]

Dear Juan,
Level set segmentation filers have a reverse expansion flag which 
can be turned off or on for changing the direction of the surface
expansion. You can change the direction of the expansion after n 
iterations and go in the reverse direction for m iterations and 
maximum number of iterations needed for both steps would be n+m. 
n indicates the number of iterations needed for reaching the 
optimal level set and m is the number of iterations needed for 
inflating or deflating the surface.
Hope this helps,
Dawood
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>>><<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<<

>> On Thu, Feb 3, 2011 at 12:05 PM, Juan Cardelino
>> <juan.cardelino at gmail.com> 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


      
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.itk.org/pipermail/insight-users/attachments/20110203/cdc8adbc/attachment.htm>