Figure 1. The power of combinations.
With a relatively small number of fluorophores, it is possible to create many different specific combinations. When the number of dyes, n, is 6, and the combination size, k, is set to 2 there exist 15 different combinations. The binary label restriction gives a more robust assay because the a priori knowledge that all cells in an image are labeled with exactly two fluorophores is used when assigning objects their label-type.