From: jim@baroque.stanford.edu (James Helman) Subject: Re: head tracking Date: 26 Nov 91 22:06:30 Organization: Stanford University Bruce Cohen asks (paraphrased): [why not put the LEDs on the head and the cameras in the room] Resolution, especially angular, is *very* important for head tracking. Consider the two systems as you turn your head: 1) Fixed cameras tracking motion of a set of LEDs on a headband. 2) Head mounted cameras tracking a set of LEDs in the ceiling. There's no comparison. #2 give very big motions on the image plane. But in order to get any kind of angular resolution out of #1, you'd need to have cameras which could zoom and pan to track the head, or lots of fixed cameras with narrow fields of view. Otherwise, the change in positions of the LEDs on the image would be too small for any kind of decent resolution. Also, if you want wide area tracking, you'd need lots of cameras in the ceiling. LEDs are cheaper. But if you're dealing with a sufficiently small area the LEDs-on-head approach might work. -jim Jim Helman Lab: (415) 723-9127 Stanford University FAX: (415) 591-8165 (jim@KAOS.stanford.edu) Home: (415) 593-1233 "The power of the computer is locked behind a door with no knob." -B. Laurel