V 3.0: Lens flares & dirt, visor reflections / water droplets, god rays, depth of field, night & thermal vision scopes, dynamic wet surfaces with reflections, rainbows, volumetric light & fog, colored speculars and many other effects.
Prior to the current, fancy-colored thermal vision systems the military have been using IR scopes and goggles only giving a grayscale image where areas of high heat were rendered with high luminosity / brightness.
This screenshot shows a modified version of the thermal vision feature addressing those old-school systems.
Wow that is real good, will we be playing with predator vision ;)