   Immersive Webcam VR Demo
  Inspired by Johnny Lee's >Wii Mote VR Tracker,  I decided to try building a virtual reality display.  Using OpenCV, I was able to get a comparable result with face tracking.  The result is that you don't need anything other than a web camera for it to work, (ie no IR LEDs, Wii motes, etc. ).  I did a quick write up on my blog, http://assertfalse.com.  The robustness could probably be improved using a few tricks.  I suspect that it is possible to create damn good VR without any additional gear on conventional hardware.   
  Cool stuff. I would have liked a bit more detail on the image processing stuff, but  your writeup was an interesting read. And thanks for putting OpenCV on my radar [smile]   ;  Thanks.  There's actually not much to the image processing component.  In OpenCV, I just opened the web cam, loaded a face classifier from an XML file, then applied it to the picture.  The classifier gives you get a list of rectangles, each representing a region of the image which contains a face.  With that information, you can approximate the position of the viewer's head in 3-space relative to the camera using the x-y coordinate of the rectangle and scale of the box (1/z).  The rest is just an issue of getting the frustum correct, which requires some hairy and boring arithmetic.   