alt Hacker Newsto get some feeling of it one can watch footage from Ukraine where drones with IR hunt soldiers at night. At the beginning of war, when soldiers didn't yet started to take it into account, there would even be whole groups walking like they would be at night feeling invisible, and that would be the last seconds before the explosion lights up the screen.
These days there is more experience with it, and for example to get "invisible" in IR one of the tricks used by the stormtroopers there is to put on an IR-protective coverall (it works to some extent and for short time) and to walk over warm asphalt.
In general even without IR the regular camera sensors these days are very sensitive, and you can pull a pretty good image out from the darkness by shifting dynamic range well down.
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You don't even need to get so "fancy" [0] as IR cameras. "Nightvision" by way of light amplification has been around for ages. [1] Even the cheap stuff I played with decades ago lit up the night like nobody's business if there was even the smallest amount of moonlight. The downside was that bright lights made the image useless, but if you're building a robot, or running the video feed back to an operator you'd simply have another non-nightvision camera.
[0] Is it fancy if IR camera tech has been around since like the 1980's or 1970's?
[1] Since WWII if Wikipedia is to be believed.
There's been some clips of Russian soldiers walking wearing either a space blanket or a sleepingbag to try and avoid IR. Unfortunately for them in those cases they were dealing with visual spectrum drones...