The Adafruit Huzzah is also fine, it can send OSC over the Network to your Show PC. Much easier to setup then Serial communication. Please be aware that you should have a solid isolated network for this types of things. (That can do both 2.4 Ghz as 5Ghz, since micro controllers most speakly on 2.4Ghz)
@emtv I don't know your set, but often lighting the thing that does not move is easier than lighting the thing that does, so carefully lighting the set with IR and not lighting the stage could be an easier solution. As long as you have good contrast between the set and the actors you can always adjust the image and invert it. I could imagine trying to always light the actors everywhere on stage and not spilling on the set could be more difficult.
@dbini Thanks a lot for that idea. I would need to dynamically split the window to do that, since the dancer might turn in any place on stage. Maybe I could on one side find the blob center and use it to place the split and have several eyes++ running on different virtual stages. I'll have to check out some day. Unfortunately I'm not very constant in my dedidaction to dig into izzy.