[Insight-users] Questions about Paramters of Curvature Flow Filter

[Lydia Ng]

Neha,

The PDE update equation is actually:

dI/dt =3D kappa * magnitude( gradient(I))

Where kappa (your "K") is the curvature of contours in the level set =
(isocontours in the image)

The continuous equation is then discretized:
I[n+1]  =3D I[n] + delta * ( kappa[n] * magnitude( gradient(I[n]) )

Where I[n] is the image at n-th time step and delta is the user =
specified time-step.

Delta is the time step which the user specifies to control stability of =
the solution.

Kappa is curvature which is computed at each pixel from the current =
level set/ image (I[n]) and thus not set externally.

Does this help?

- Lydia

-----Original Message-----
From: Neha D [mailto:itkneha at yahoo . com]=20
Sent: Sunday, October 26, 2003 4:08 PM
To: Insight-users at public . kitware . com
Subject: [Insight-users] Questions about Paramters of Curvature Flow =
Filter

Hi All,
The CurvatureFlow filter requires two parameters, the number of =
iterations to be performed and
the time step used in the computation of the level set evolution and are =
set by
the methods SetNumberOfIterations() and SetTimeStep() respectively.
The level set function is=A0evolved under the control of a diffusion =
equation where the speed is proportional to the curvature of the =
contour:
I(t) =3D K. delta(I)
question is-->=20
What is "K" and how it's value is decided? While using Curvature Flow =
Filter, we don't set this paramter while it plays important role in =
calculating the level set.
Any input on this appreciated.
Thanks,
Neha
=A0
=A0

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