These are micro CT scans. My object(s) of interest are shown above (crystals and bubbles). What makes this hard (at least for me) is to only threshold the bubbles which are in contact with crystals (Exterior). Since I also need to know the crystal bubble relationship of each crystal in the melt (There can be upwards of 10 per dataset), I have to mask out each individual crystal + their associated bubbles.

Image showing the desired effect on a single frame

Image showing desired effect across 150 frames

What I want to avoid is brute forcing it. So before I spent time trying to write up a little program, is there a plugin or tool that I might just be unfamiliar with that can do this?