As discussed today in the MITK meeting I was having trouble with applying 3d region growing to a dataset of mice lungs. The task was to segment the lumen of the airways. I set the seedpoint in the middle of the lumen (see upper left corner in screenshot) and clicked "run segmentation"

Unfortunately, no segmentation was created at all.

As a sanity check: when I instead apply region growing 3d to the bright border of another airvessel everything works as expected:

My semi-educated guess is that the voxel value of 0 could be giving issues?

Another observation: If I set the seed point to a pixel close to the border (which has a non-0 value but still low intensity) the region growing seems to work (as long as I don't touch the "define thresholds" slider which defaults to [0,1 38.3]:

HOWEVER, as soon as I modify the lower bound of the "define thresholds" slider from 0,1 to 0 it again does not work.

Best,

Fabian