Help with Watershed


I am currently using ImageJ to analyze some pictures like the following one:

I need to obtain the coordinates of the mass centre for each particles in the picture.

To do that I do first: Image-Color-Split Channels. I choose the best Channel (the green one), then I do the Threshold and then I use the Watershed option (Process-Binary-Watershed).

However, the Watershed option works only for the white and yellow particles and not for the black ones. In fact, for the black particles there is an oversegmentation and then with Analyze Particles I am not able to recognize the black particles. This is mainly because the black particles touch and overlap each other.

I do the threshold twice, first for the white and yellow particle and then for the black particles.

Is anyone able to suggest me what to do to improve my results from the watershed of black particles?

Many thanks.

Hello @Claudia1 and welcome to the ImageJ forum!

You might want to try using the Distance Transform Watershed plugin instead of the regular watershed command, so you can play with some methods and parameters to see if you obtain a better object separation.