Apple’s Israeli PrimeSense team has developed a 3D camera system intended for Augmented Reality (AR) use. It features a light beam for optical 3D mapping and depth sensing. Connected to Apple’s AR glasses, it can interact with a hovering holographic interface, just by moving your hands.
http://www.techradar.com/news/apple-patent-paints-a-future-of-ar-glasses-and-gestural-controls