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So the main idea of the tool is similar to the thresholding voxel QC tool - it can easy adjust the inclusion stickout. The difference is in the shape of the resulting border of inclusion. Morphology doesn't take into account the transparency of the inclusion and can increase inclusion volume to the area, where you cannot see anything resembling inclusion. As for thresholding tool, it cannot increase inclusion volume to transparent area. Also morphology increase its volume uniformly in all directions, thresholding tool - the increase depends on inclusion transparency.
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The result at the top (thresholding) has better borders border - that border better corresponds to the the border between transparent and non-transparent areas. On the other hand, morphology eliminated transparent mini-holes in inclusion and smoothed the borders of reprojection.
So in most cases we advice to use thresholding tool for adjusting inclusion shape. Theoretically, you can apply morphology tool for inclusions with transparent parts and the result might be better than for thresholding in this case.
Also multiple application of this tool is useful if you want to remove small transparent holes in inclusion or split big inclusion from other, connected by thin necks. This techniques are more complicated (but very useful) and described in chapter "Practically important cases".
Inclusion merge
Practically important cases
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