How can I measure particle size distribution from an AFM scan

Hi,

I have an image obtained from an AFM scan (where each pixel represents height) and I recognize nano-features when I'm using mean curvature analysis. Now I want to measure the mean size of these features. I tried to use watershed analysis on the original scan, but it appears that Matlab recognized only half of the features in the scanned area.

I would be happy if someone could advice me and offer a better method to calculate it.

thanks a lot

[KAE]

This package may help.