Natasha,
Have you read:
http://imagejdocu.tudor.lu/doku.php?id=gui:analyze:analyze_particlesMichael
> How can I understand in more details some plugins?
> e.g. I want to know how the plugin analyze_particles detects the regions
> depending on the particles size? Which algorithm does it depend on?
> Anyone can help me and give me a documentation or articles?
> I can follow the code but it seems to take so long time to understand it..
> I'll be thankful for any help.