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

[Vaaksiainen]

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