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

[Kishore Mosaliganti]

Hi Juan,

I think your alternative using 1 is the simplest that comes to my mind.

Kishore

On Thu, Feb 3, 2011 at 1:40 PM, Juan Cardelino <juan.cardelino at gmail.com> wrote:
> Hey Kishore,
>
> No, I intended to take that into account.
> Actually, the 10 pixels was an example, I originally intended to move
> the curve outwards a fixed amount of euclidean distance. But if I
> could live with that aproximation too.
> I'm segmenting a sequence and I want to use the segmentation of the
> previous frame as initial condition for the next, so actually I don't
> care doing a rough approximation
> Thanks
>
> On Thu, Feb 3, 2011 at 4:27 PM, Kishore Mosaliganti
> <kishoreraom at gmail.com> wrote:
>> Hi Juan,
>>
>> For moving exactly 10 pixels, are you thinking of ignoring different
>> pixel widths in diagonal neighbors and face neighbors at a given pixel
>> ?
>>
>> Kishore
>>
>>
>> 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
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>>
>