Identity of multiple leds

[Jerry]

Two questions.

I want to track two leds, one on the head and the other somewhere else. How can I guarantee that the one on the head is always assigned the same identity each time I run the experiment? Will this occur if the two leds are always in the same location when I activate PPT?

With a 4-camera PPT, if one of the leds goes out of the field of view of two cameras, will it still be tracked?