[IGSTK-Users] Fwd: [ITK-users] Geodesic Active Countours

[Fabian Torres]

Hi all.

I have been trying to use the GeodesicActiveContourLevelSetImageFilter to
extract the surface of an object in an image.

I have managed to use this in 2D and works fine, my problem comes when I
try to use it in 3D images.

If I put the propagation, curvature and advection scaling in 0 I have an
output from the geodesicActiveContourFilter pretty similar to the input
image, but if I change the scaling factors even just a little I get an
empty image as an output i.e. all pixels have the same value.

typedef
itk::GeodesicActiveContourLevelSetImageFilter<FloatVolumeType,FloatVolumeType>
GeodesicActiveContourFilterType;
GeodesicActiveContourFilterType::Pointer geodesicActiveContour =
GeodesicActiveContourFilterType::New();

geodesicActiveContour->SetPropagationScaling(0.1);
geodesicActiveContour->SetCurvatureScaling(1.0);
geodesicActiveContour->SetAdvectionScaling(0.1);
geodesicActiveContour->SetIsoSurfaceValue(255);
geodesicActiveContour->SetMaximumRMSError(0.02);
geodesicActiveContour->SetNumberOfIterations(100);
geodesicActiveContour->SetFeatureImage(surfaceFilter->GetOutput());
geodesicActiveContour->SetInput(segFilter->GetOutput());
geodesicActiveContour->Update();

The feature image comes from a surfaceFilter that is some preprocessing
with a sobelEdgeDetectionImageFilter, the input data comes from the
segFilter that gives an image with an segmentation of the object, where the
object pixels have 255 value and the background has 0 value.

but as I said if I put the scaling factor as 0

geodesicActiveContour->SetPropagationScaling(0.0);
geodesicActiveContour->SetCurvatureScaling(0.0);
geodesicActiveContour->SetAdvectionScaling(0.0);

The output image does have different values around the object surface.

Can any one help me with these?
Thanks

-- 
Fabián Torres Robles
Maestria en Ciencias en Ingeniería Electrónica
Ingeniería en Sistemas Electrónicos
tel. 58081280, 0445534661338
e-mail fabian.trobles at gmail.com, dae.wong at gmail.com
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