Dimensional analysis of irregularly shaped fibers

Hi all you good folks,

I’m trying to carry out some dimensional analysis on some fibres imaged via SEM. The problem is these fibers are always cylindrical, but sometimes have this annoying y-shaped/tri-lobal morphology (see below), so I can’t, or at least I don’t think I can, use diameterJ to characterize them. Is there any plugin that would help me with carrying out dimensional analysis? I’m tracking how these fibers degrade over time, and would like to compare cross-sectional area (across the length of the fibers, as these aren’t necessarily and can’t be nicely segmented as they are in this image) between samples at different points of decomposition.

Thank you,