Hi everyone, thanks for your feedback and helpful tips. Sorry for my imprecise question.
My goal to get and store the ROI around each nucleus in the ROI manager.
as @imagejan has pointed out, findmaxima failed as it gives only the
@iarganda thanks for introducing me to MorphoLibJ, that looks powerful. However, in the result you have posted there are still touching objects that where not separated.
I got the results I was looking for using an approach with thresholding followed by Analyze Particles + Watershed as @iarganda pointed out:
run("Convert to Mask");
run("Analyze Particles...", "size=0-inf add");
Here is what I get:
I suppose my initial train of thought went completely into the wrong direction Thanks for your help!