stefanv/scikits-image — comment on commit b83ece8b0583093ea1692af4bcf84f0fb8f53066
File: skimage/morphology/ccomp.pyx line 73
By tonysyu:

Maybe there should be a note to emphasize that, unlike other implementations, 0 is not treated as a background value.

I read over the docstring, but didn't really think about the implications. It wasn't until I saw the examples that I realized the implications of "same value".

Alternatively, have you thought about adding a flag to mask out the background values? You mentioned on the mailing list that it's fairly simple, but I imagine it would be common enough to warrant such special treatment. Also, a parameter would naturally emphasize this (for me) unusual behavior.