Tracking moving objects automatically has up until now involved moving the camera. That's obvious, really.
But it wasn't obvious at all to a team of Japenese engineers who have done it a different way, with unbelievably good results. They're system can accurately track a bouncing ball, for example, keeping it in the centre of the picture.
They do it by moving a pair of mirrors, one for vertical movement and the other for horizontal tracking. Beause the mirrors have a much smaller intertia than an entire camera, they can not only track objects incredibly fast, but are able to use virtually any camera - including very high-quality ones, to ensure a good picture.
And the technique is reversable too.
By putting a projector in place of the camera, they can display moving images on moving objects. We're struggling to think of practical applications for this but it doesn't stop it being a remarkable technology demontstration.
Of course, there's more to it than a pair of mirrors. There's some pretty clever software and image analysis going on here too.
Thanks to our VFX correspondent HaZ for spotting this.