Far from being a last hurrah filled with new product announcements, Bill Gates' CES keynote largely focused on Microsoft's existing offerings. But one technology currently in development did intrigue - a visual recognition system for mobile phones.

Gates demonstrated various potential uses for the technology, which recognises images picked up by the phone's digital camera and provides further information it considers might be useful to the user. First off, he pointed the camera at Microsoft colleague Robbie Bach and the phone instantly recognised him, flashing his name up on-screen along with the note "He owes me $20".

He also showed how the system could be used to recognise buildings and landmarks - it picked out and named a Las Vegas restaurant and provided a link to further information, including the restaurant's menu. It also offered to show the fastest route to the restaurant, showing the journey in 3D.

Gates didn't reveal any details of when the technology might come to market, although judging by the brick-sized prototype, we may have to wait a while.