http://www.tomshardware.com/news/ace...-mr,34266.html

As far as we can tell, and as far as Acer would say, the company?s mixed reality HMD is actually just a VR HMD with inside-out tracking.
We?ve been clamoring for more information (any solid information, really) on Acer?s upcoming mixed reality HMD specifically, and any of the other supposedly upcoming XR HMDs from other PC makers generally, but so far any details have been sparse. We learned a bit about the Acer HMD at GDC, but...not much. At Acer?s NYC event, we learned a little more. And it was a mixed bag.


The sensor bar on the HoloLens comprises four ?environment understanding cameras,? two on each side; a depth camera; an ambient light sensor; and a 2MP photo/HD video camera. Some of these are off-the-shelf parts, whereas Microsoft custom-built others.
The environmental sensing cameras provide the basis for head tracking, and the (custom) time of flight (ToF) depth camera serves two roles: It helps with hand tracking, and it also performs surface reconstruction, which is key to being able to place holograms on physical objects. (This is not a novel approach--it?s precisely what Intel is doing with its RealSense 400-series camera on Project Alloy.)

These sensors work in concert with the optics module (described above) and the IMU, which is mounted on the holographic lenses, right above the bridge of your nose.

Said the presenter, ?Environment cameras provide you with a fixed location in space and pose,? and the IMU is working fast, ?so as you move your head around...you need to be able to feed your latest pose information into the display as quickly as possible.? He said that HoloLens can do all of this in <10ms, which, again, is key to preventing ?swimming? and also to ensuring that holograms stay locked to their position in the real world space.