From: "PSOTKA, JOSEPH" <PSOTKA@alexandria-emh2.army.mil>
Subject:      RE: Sci-VW: TECH: Distortion in VR view
Date:         Fri, 29 Jan 1993 11:42:33 CST



Some of this apparent distortion is because of the apparent size of
the field of view.  The Field of View (FOV) on your monitor is very
different from the FOV on the head-mounted display.  The SGi monitor
if you look at it from arms-length has a FOV of about 40 degreees;
while the Flight Helmet has a 100 degree FOV horizontally.  That's why
it looks better on the Flight helmet.  You should change fovy to
correspond to the field of view of the display.

There are however other effects that lead yoiu to think there is a
distortion.  One of these is that fact that we interpret ourdisplay
when we look at it in terms of the 180 degrees or so of our natural
full eye field of view.  Becuase we interpret the 40 o monitor FOV as
if it were 180 o, the image appears distorted.  See my report:

Psotka, J.  (1992) Virtual Egocenters as a Function of Display
Geometric Field of View and Eye Station Point.  Virtu-l Bulletin
Board,9 Jul 1992

for some ideas about this.

joe