[Insight-users] Levelsets-v4 curvature term drives circles to squares (2-D) (+other issues)

[Vaaksiainen]

Update to this question and some credit to authors :) now that I've
tried it, Chan-Vese levelset works nicely, and although a single
iteration is slowish, the convergence is very fast from the initial
circle initialization (~comparable with v3 snake in total time). I
remark, that default value of Heaviside epsilon is kinda high, so
changing that was my first solution. The original question with plain
curvature or geodesic active contour remains open still.

I try not to profile spammer, so I also attach here my thanks to
Arnaud regarding my previous question
(LevelSetEquationTermContainer->SetInput() ? ).

Best,

-Vaaksiainen

2012/12/17 Vaaksiainen <vaaksiainen at gmail.com>:
> Hi,
>
> I'm learning Levelsets-v4 hard. Currently, after not getting the
> convergence appreciated, I tried the following:
>
> I set up LevelSetEvolution following the
> itkSingleLevelSetDenseImage2DTest -example, but I use only propagation
> or curvature terms one at a time. I set the feature images unitary,
> and initialize the levelset as small circles (equi-spaced).
>
> Problem: curvature term drives circles towards squares (really
> sharp-edged NxN pixel squares eventually), while obviously should not.
> Somewhat similar happens with the propagation term alone, where I find
> speed along coordinate axes to be dominative.
>
> What I might be doing wrong here?
>
> Another question, is it possible to obtain (approximately) similar
> behaviour using GeodesicActiveContourLevelSetImageFilter and
> Levelsets-v4 framework with propagation, curvature and advection
> terms. I tried, but obvious reasons (mentioned above) already
> cancelled this study. Also: number of iterations per time unit seems
> to be drastically lower (hundred folds) with the new framework.
>
> -V