AVG has attracted attention with a pair of spectacles designed to fool facial recognition systems. Though they build upon previous attempts, they are still very much at the concept stage.

You may remember the first such gadget was unveiled a couple of years ago by Isao Echizen of the National Institute of Informatics in Japan. He and his team worked on the idea after noting that it was now possible to quickly identify many (though still a minority of) people by cross-referencing their photograph to sites such as Facebook.

Echizen’s solution was a pair of spectacles which had the option to switch on several LEDs. The resulting light beam is in the near-infrared frequency and is thus invisible to the human eye, but can be detected by camera lenses. The resulting visual noise undermines facial recognition software.

AVG have built the LED technology into their concept prototype and noted that, as shown above, it can certainly be enough to defeat Facebook’s own face recognition. However, it poinst out that even many cellphone cameras used today are sophisticated enough to filter out light at wavelengths invisible to human, thus producing pictures that better replicate what the eye sees.

Its solution  is to use retroreflective materials. These are surfaces which reflect light back in precisely the same direction from which it struck the surface, rather than scattering it at angles like most surfaces. Such materials are commonly used in road signs, meaning they can be visible in dark conditions thanks only to the illumination from car headlights, rather than the sign requiring its own light source.

The front of AVG spectacles are covered in the material, meaning the frames show up in camera shots as a particularly bright outline. The idea is that this creates so much contrast between the spectacles and the rest of the image that it’s no longer possible to detect enough contrast between facial features for automated recognition to work.

AVG is displaying the spectacles at the Mobile World Congress event in Barcelona but describes them solely as a proof of concept, with no current plans for a commercial release. It says the current model, even with the retroreflective solution, still has major limitations: it only works when a camera uses a flash, and it doesn’t work with high-end cameras that have a particularly large dynamic range.