I see, so the stats are taken on the original image.
I just wanted to get the sizes of my connected components withouth caring too much about the original image. How can I do this?
So you’re not interested in the intensity statistics under each label, you are interested in the physical size of the region the label occupies? If yes, then the relevant filter is LabelShapeStatisticsImageFilter and not LabelIntensityStatisticsImageFilter.