Night vision goggles? I always thought K-9’s could see pretty durn good in the dark. I know mine can see stuff that I don’t have a clue is there. (Of course some people tell me I’m pretty clueless...most of the time.. :>})
the goggles let them see what forms through concrete walls.
Infrared would allow the dog to see heat, which even their excellent night vision doesn’t make capable naturally
Particularly tanks or other metallic objects I reckon