Measuring cell roughness

I am extremely new to image processing and am currently struggling to find the best method to measure the roughness of cells. I tried using the roughness calculator plugin but the output do not seem to represent the cells. Could someone walk me through using Directionality for this use case?
PA01.tif (799.0 KB)
Ethanol03.tif (799.0 KB)


I would first point you to this older thread that you may find helpful:

Basically - start with how you want mathematically define ‘roughness’… once you have a clear view on that - share it with us and we can perhaps better tailor/assist you in your analysis.