Relying on your tablet's on-screen keyboard saves you from having to carry clunky accessories, but it also gobbles up a good chunk of usable screen real estate. So Fujitsu researchers are working on a happy medium that uses the tablet's camera to track your finger movements on a desk, as if you were typing away on an invisible keyboard.
It's not unlike those laser keyboards that have been kicking around for a few years, but this approach is powered by intelligent software that actually makes it usable. Since everyone has different shaped, sized and coloured hands, the software has to spend a bit of time learning how a user types before there's any kind of useful accuracy. But when school's over, it does appear to be a plausible alternative to a physical keyboard.
As long as you're not a die-hard touch typist who needs the tactile feedback, and as long as Fujitsu considers this research more than just a way to write off R&D money.