[Insight-users] Suitable parameters for Level set algorithms needed.

[Rainbowfrog at web.de]

Hello 

I took the code found in :

FastMarchingImageFilter.cxx
ShapeDetectionLevelSetFilter.cxx
ThresholdSegmentationLevelSetImageFilter.cxx

of the Itk examples, and modified it to fit into my segmentation program.
I allow the user to set the most important parameters for these algorithms
over a dialog via sliders. I don't know much about the mathematical background
of those algorithms though (for example I couldn't solve differential equations
by myself, but I have read in the Itk software guide that the algorithms use them)
that's why I don't know for some of the variables which standard values make
sens, and which range of values I should allow the user to set (for a slider bar
this means,depending on the parameter: which values I should take as minimum 
and maximum for the user to set). I have listed the default values for the
parameter sliders that I use for each of the algorithms, some of them were in
the examples , and for some of them I just guessed a value.

I don't get good results with them, for the ShapeDetectionLevelSet I don't even 
get a valid result. Which standard values , minimum values , and maximum values
would make sens for them ? Does anyone know good starting values ?

I'd be glad if someone could help me with this.

Regards
Philipp

Standart parameters I'm using:


FastMarching:

	For the Smoothingfilter
		(int) Iterations = 5
		(double) Conductance = 9.0

	For the main algorithm:
		(double) timeTreshold = 3.0
		(double) sigma =3.0
		(double) alpha =-3.0
		(double) beta  =3.0
		(double) stoppingTime = 15.0

		+ at least one seed point


Shape Detection:

	For the smoothingfilter
		(int) Iterations = 5;
		(double) Conductance = 9.0;

	For the main algorithm
		(double) sigma =3.0;
		(double) alpha =(-3.0);
		(double) beta  =3.0;
		(double) initDistance=0.0;
		(double) curvatureScaling = 10.0;
		(double) propagationScaling = 1.0;
		(double) maximumRmsError =0.02;
		(int)    Iterations =800;

		+ at least 1 seed point

Threshold Level Set:

	(double) initDistance=0.0;
	(double) curvatureScaling = 1.0;
	(double) propagationScaling = 1.0;
	(double) maximumRmsError =0.02;
	(double) upperTreshold =250.0;
	(double) lowerTreshold=5.0;
	(int)    Iterations =1200;

	+ at least 1 seed point



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