Still curious - not stirring the pot. Per the WAC the IR device cannot be "capable of projecting a beam onto the target".
I believe typical thermal imaging devices are passive, i.e. not projecting anything, simply receiving IR energy. That said they do require signal processing, i.e. batteries to operate.
https://www.atncorp.com/howthermalimagingworks
??
There are some systems that use a laser that is only detectable with an infrared imager. They're mainly used by military, I think.
