Re: Field Sequential Stereo Lag

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Angus Dorbie (dorbie++at++sgi.com)
Fri, 11 Dec 1998 17:50:24 -0800

Greg Harrison wrote:
>
> We're using field sequential stereo with Performer and when moving the
> eyepoint rapidly through the scene, the objects that are near the eyepoint
> (and following it) appear to lose stereo, separating into two distinct mono
> images, splitting along the direction of travel. Is there any way to
> counter this effect, either with callbacks or some other tricks?

Sounds like a sync issue. You need to draw left & right eyes at the
same
time then display sequentially. It sounds like you are drawing left
displaying then drawing right then displaying creating a displacement
between frames. This affects the separation of an object
on sequential frames.

CANCEL that, I'll leave it there for reference though.

Actually it just occurred to me that this is probably due to a different
inherent problem for this display. Your brain doesn't know which two
images
are coherent. In an image stream containing left1, right1, left2,
right2,
etc your brain might perfectly reasonably assume that right1 and left2
are
a stereo set. This could be your problem if you are rendering at full
video
frame rate. So as the object displacement due to motion reaches greater
than 50% of it's displacement due to stereo effects this is likely to
happen.

It's an interesting problem. For your application you probably have to
go to some other display technology where the stereo left & right images
are in sync. The thing I said not to do at the start may also be an
option to improve the situation but I don't know if it would work. It's
worth a try.

Cheers,Angus.

>
> Greg Harrison
> Air Force Institute of Technology
>
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