welcome on the forum!
In ImageJ/FIJI, you could try to Threshold your image and use the Analyse Particles with the option Bare Outlines in the show dropdown menu.
Please, find below a small imagej macro that will generate a rainbow-like image from blobs and create the outline image.
// open the blobs image and threshold it
run("Convert to Mask");
// use analyse particles with the output "Count Masks"
run("Analyze Particles...", " show=[Count Masks] exclude");
// So you get a rainbow-like series of objects
// threshold and use the Bare Outlines output
run("Analyze Particles...", " show=[Bare Outlines]");
// to convert the image to 16-bit
make16bit = true ;
if (make16bit) run("16-bit");
If you are looking for something different, could you provide a link to dowload one of your image ?