Very new to this, I'm trying to measure the surface area of some small aquatic ferns (Azolla) with ImageJ but having issues. Using 'Adjust > 'Color threshhold' (after setting scale and cropping) I can highlight roughly 90-95% of the area i want simply sliding only the saturation bar (and i can get similar results with brightness only), but I have 2 issues: a) the darker growing tips don't get included (which i want) while the roots below do get included (which i don't want). See pic below for reference (different image to top one, i know).
I have multiple images so obviously trying to keep it as simple as possible.
Unfortunately the Hue bar doesn't work especially well for me. Probably due to poor photography setup, most of the pixels representing the Azolla are up around the yellow-orange spectrum, not green as i'd hoped. The blue-green pixels in the picture below represent the background,
Also the dark growing tips complicate it again.
As mentioned i'm very new to this so if there's any functions within ImageJ/Fiji or tips you can offer that would help to get more accurate measures i'd really appreciate the help