[ITK-users] Too many label objects detected when only 3

[Chr. Rossmanith]

Hi,

your image isn't a true binary image but has some gray values close to 0 
(black) and some gray values close to 255 (white). I've converted it to 
a pure black-white PNG and now three regions should be detected. I guess 
JPG does some anti aliasing which introduces the additional grey values.

Christina Rossmanith



On 10.04.2015 14:32, Francisco Lopez de la Franca wrote:
> Hi all.
> I've just tested itk::BinaryImageToShapeLabelMapFilter with an B/W 
> image (see attachment) containing only 3 object.
>
> I call the following methods:
>
> > binaryImageToShapeLabelMapFilter->ComputePerimeterOn();
> > binaryImageToShapeLabelMapFilter->SetInputForegroundValue(255);
> > binaryImageToShapeLabelMapFilter->SetOutputBackgroundValue(0);
> > binaryImageToShapeLabelMapFilter->Update();
>
> > LabelMapType::Pointer labelMap = 
> binaryImageToShapeLabelMapFilter->GetOutput();
>
> > int nrOfLabelObjects = labelMap->GetNumberOfLabelObjects();
>
> When I display the number of of label objects, the result is 246.
>
> Does anybody know why this behaviour?
>
> Thanks a lot.
> My best regards.
>
>
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