[amaxerlite]

As someone who's worked with computer vision, I doubt this is fully effective. It might prevent an exact match, but a good facial recognition algorithm can still whittle down the total possibilities. That's because your cheeks, ears and nose are also used as identifying features. The only effective cover is something that covers whole face.

[mcantelon]

Yeah, for it to be truly effective it would be to have some sort of halo of IR LEDs that are brighter than the ambiant surrounding light. This is probably not viable due to power requirements/cost.