Figure 1: Diagram of a hypothetical HMD for calibration purposes. The HMD consists of two small real screens mounted directly in front of the viewer’s eyes, and uses optics to create larger virtual screens at a longer distance away to allow users’ eyes to focus on the imagery. For proper calibration, graphics software needs to know the precise positions of the viewer’s pupils and the exact positions and sizes of the virtual screens, in some coordinate system. Head tracking will provide the mapping from this viewer-attached coordinate system to the world coordinate system to allow users to look and walk around.
Another interesting fact that the Diagram brings to light, that probably most people do not realize, is that people with larger noses do not see the same as people with smaller noses.
Try it. Lay your finger flat on your nose (to make your nose longer by the thickness of your finger). Now it is much harder to see. Remove your finger and your able to see again.
Weird how blocking a small portion of your vision (that is served by both eyeballs) makes it hard to see. I guess each person’s brain adjusts as they grow up (doesn’t it?) and thus each person can see (though not the exact same) with the nose they have.
Plastic Surgery to make your nose bigger would make it harder to see also.
An interesting factoid I never considered until I saw your drawing. Enlightening.
i like the graphic! Is it your own illustration or taken from somewhere else?