New the forum. I did quite a bit of searching and exploration for my answer with no success. I have several thousand photos of urchin guts taken using a stereoscope and I need to count and identify particles >0.5mm as red, brown, or green algae. Needless to say, this takes forever to do manually. To my understanding, ImageJ can automatically segment and count particles, but can it count particles based on a defined RGB threshold? For example, some urchin diets are a mixture of red, brown, and green algae. Each particles can assume multiple shades of their associated color (i.e., RGB), but nonetheless are visually distinct from one another. So, using imageJ, is there a useful method for segmenting/counting and identifying particles based on an RGB color threshold? I’ve attached an image for reference.