IBK
IBK (Image-Based Keyer) is a non-native node to nuke, it was developed in a studio.
Increasing to a large size in IBKColour node to clean the plate may cause atrfacts, instead, we adjust darks to correct the edges and use stacked IBKColour nodes to shrink the objects. Then connect to IBKGizmo node to show the objects.
We can create two green constants, one from the bright region, one from the dark region, to even the green screen.