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Date: Wed, 23 Oct 91 23:48:06 -0400
From: Dave Stampe-Psy+Eng <dstamp@watserv1.uwaterloo.ca>
Message-Id: <9110240348.AA18884@watserv1.uwaterloo.ca>
To: glove-list@karazm.math.uh.edu
LEEK@QUCDN.QueensU.CA writes:

>A friend of mine recent bought a used colour video camera from a store.
>(It's one of those pre-camcorder thing with external VCR required)
>The video cameria comes with a attachable B/W monitor.  It comes with a
>len to correct the focal distance for viewing through the eye piece.
>These would be quite useful for mounting onto a helmet.  All the electronics
>are built and accept a composite video (NTSC) and DC power.  No messing
>around required.  There is a switch to flip the image (for viewing from the
>other side of the camera.)  This comes in handy as you can get the two monitors
>out of the way of each other by flipping one.
>
>He got the whole thing for about $150 Canadian.  The owner of the store
>told him that he might be able to find defunction camera for parts at a much
>cheaper price...  Look around pawn shop & used video equipment store around,
>you might be able to find something useable for a VR homebrew project.
>
>My second idea involve splitting the screen into 2 side for each eye.  This
>save you 50% cost & weight at the expense of losing resolution.  Some optic
>trickery is required...
>
>                                _______
>                              |       |
>                              |       | ---->   This half for the right eye
>                             -+- - - -+-
>  This half for the left<---- |       |
>                              |_______|
>
>                               (screen rotated
>                                by 90 degrees)
>
>By dividing the screen this way, you can get a wider aspect ratio as a side
>effect. :)

>K. C. Lee

The problem I see with the camera viewfinder is the tiny FOV (<20 degrees).
This makes it difficult to navigate in a virtual world.  A series of 
experiments performed recently (Restricting the Field of View:
Perceptual performance effects, in Perception and Motor Skills #70)
demonstrated severe degradation of visual-motor coordination and poor
"conceptual mapping" with display "windows" (actually holes cut in
a mask) for any size less than 30 degrees wide.  Subjects performed
a variety of simple tasks, including following a twisted line on the
floor and exploring a room.  Little degradation was seen with "display"
FOV's grater than 100 degrees.

I love the resolution, size and price of the camera viewfinders myself
and wish the FOV was better...  In fact, if I can do something about
the weight, I'm considering using 4" B&W TV's with a simple lens to 
make BIG viewfinders with 54x40 degree FOV's.

The split display idea will also result in a small FOV, mostly because the 
mirrors needed to get the image to the proper eyes will put them too
far optically from the eye-lenses.  Another possiblilty is to use a
640x200 monochrome LCD panel (they used to use them in compatibles) and
use one side for each eye.  Pretty easy to see how that would work, and
you can put it REALLY close to the eyes (= big FOV).  Now to find one...


--------------------------------------------------------------------------
| My life is Hardware,                    |                              | 
| my destiny is Software,                 |         Dave Stampe          |
| my CPU is Wetware...                    |                              | 
| Anybody got a SDB I can borrow?         | dstamp@watserv1.uwaterloo.ca |
__________________________________________________________________________