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HMinimaImageFilter(float-image)
GrayscaleFillholeImageFilterr(Hminima-result)
SubtractImageFilter(Hminima-result,fillholes-result)
BinaryThresholdImageFilter(Substract-result) #bg==0 fg everything except 0
ConnectedComponentImageFilter(threshold-result)

But the result is not as expected.
For one I wonder how I can achieve a threshold as fg is everything except 0.
Second the subtraction does not yield 0 any where. Why that? Is this a rouding
error problem?

Is there a better way to achieve this goal?

Many thanks for any help or hints
Lynx