I'm wondering what type of *threshold* would work well for distinguishing features that are very small (small in the *xy* sense) in comparison with the full spread, if that makes sense. The `graythresh()` function in Matlab that uses the *Otsu* method doesn't work too well for my data. *Otsu* is a clustering method where I think the # of pixels should be similar in each class, which is not the case for me so when I employ it I get a threshold that is way too small and falls well within a lot of the background noise that remains even after filtering.