Hi!

I think about a advanced version of the Process -> Binary -> Watershed method. As far as I understand the method work as follows:

0. Input binary image

- Calculate the EDM
- Find maxima on the EDM
- Outgoing from each maxima, make dilation** : “It then dilates each of the UEPs (the peaks or local maxima of the EDM) as far as possible — either until the edge of the particle is reached, or the edge touches a region of another (growing) UEP”
- Add split point where two regions are touching.

**As for the dilation: I guess the dilation is done on the EDM map? Outing from a maxima, a region growing algorithm is applied with a tolerance of 1. For next dilatation the tolerance is increased by 1. Right?

If my assumptions are correct, then I would like to propose the following change:

Instead of using the maximas on the EDM as seed points for the region growing (or dilation), we could use the maximas on the symmetry map calculated by the fast radial symmetry technique (FRS). It seems for me, that the splitting capability could be improved by that way. However, it needs many more parameters so it is not meant to be a replacement for the current watershed command.

The FRS technique is descriped here:

The FRS technique is already implemented for imagej by @ThomasBoudier .

We could copy and adapt the code easily.

Who did implement the Process->Binary->Watershed command and can comment on this? Maybe @Wayne ?

I would be happy to hear your opinion.

Cheers,

Thorsten