Another Youtube video shows Microsoft HoloLens demo driven by gesture control:
Engadget says "There are at least four cameras or sensors on the front of the HoloLens prototype." Mashable writes "Based on a quick look at the headset, it appears to have four front-facing cameras that could be used to detect the positions of the user's hands as she interacts with holographic objects."
Another Mashable article says "The augmented-reality headgear is full of sensors, but the most powerful one may be the 3D depth sensor. It’s the same one you’ll find in the Kinect and it is capable of building a detailed 3D mesh map of a room and everything in it. Once HoloLens knows what’s in the room, it can essentially drape 3D imagery over it so that it looks as if the digital objects and textures are part of the same environment as real world walls and furniture."
Another Microsoft video briefly shows HoloLens internal design:
Wired reports that "the headset is still a prototype being developed under the codename Project Baraboo, or sometimes just “B.” Hololens chief inventor, Alex Kipman has "been working on this pair of holographic goggles for five years. No, even longer. Seven years, if you go back to the idea he first pitched to Microsoft, which became Kinect."
Seattle Times reports "The company isn’t saying how much a HoloLens will cost or when it will be broadly available but it’s likely to cost less than a high-end computer. Chief Executive Satya Nadella said it’s intended to be accessible to consumers as well as business users, though the latter seems to be a primary target."