Instead of scanning fingerprints to determine a person is who they say they are (unless they're holding someone's dismembered finger, naturally), Fujitsu's vein sensor does the job...only in a much smaller device, measuring just 29mm wide, 11.2mm tall, and 29mm thick.
In fact, the hand doesn't even have to touch the sensor, with a small wave over it being enough to identify the person by snapping up to 20 photos and cross-referencing them with stored images of the user's hand, according to Fujitsu. It could be added to laptops or even cellphones in the future, as a means to a very secure end. Unless you're holding someone else's recently-dismembered hand, naturally. [Fujitsu via UberGizmo]