Creating a ROI out of a ROI boundary

[Rafael Ballester]

Hi all,

Given a ROI, I would like to obtain via ImageJ API another ROI consisting of its boundary pixels.
I guess this may be done by dilating the original ROI's mask and then substracting the original ROI's mask from it. But even if I do that, I can't figure out a way to create then a new ROI from the resulting mask. Any idea on this (or some different path to get a boundary ROI)?

Thanks,

Rafa