After few seconds ingame the FLIR gets washed out and it becomes very hard to distinguish anything apart from vehicles with running engines or people on the ground.
I played around with my video settings - PiP detail, Texture detail, viewdistance, AF, ground detail and so forth, I even changed video memory from default to very high, to high, to normal, to low, to default again and tried older video drivers - nothing (I'm now on Catalyst 12.3). PC specs are in my sig.
This is how it should look like (moments after loading the game):
And this is how it looks after 1 or 2 seconds: