P3D Re: Reality of Seeing

[Paul Talbot <ptww@xxxxxxxxx>]

Gabriel,

Thanks for a fascinating post.  It definitely warrants more
investigation!

Paul

Gabriel Jacob wrote:
> 
> Paul writes (in another post):
> >Great post, Bruce.  Stereo slides appear "more realistic" than flat
> >images to me, but I've never felt them as being "real" to the same
> >extent that many others do.
> 
> It looks like you and I are the only ones. Seriously I think there
> are others with this affliction! ;-) I think I have commented on
> that in the past and I know you have.
> 
> My guess as to why is because of accommodation (eye focusing far or
> close). Even though it is a very weak way of determining absolute
> distance, I think certain individuals are more sensitive to it's
> effects. This is not to say they can resolve distances very well
> but they can tell if it is close or far away. Therefore in the
> case of viewers (2-D and 3-D) I (as also Paul does) doesn't get
> fooled that the distance is at the place the image suggests it
> is. For people that are not sensitive to accommodation they sense
> the image as if it was in reality.
> 
> In my informal experiments I had tried viewing one side of a stereo
> pair (can be done with a 2-D slide for that matter) and looked at
> it with one eye and with the other eye stared at a blank wall far
> away. Superimposing the image onto the wall, so that the eye looking
> at the blank wall also "sees" (brain actually sees this image) the
> image, what happens is that the brain is getting two different
> accomodation signals. One where the eye viewing the image is sending
> a tensed muscle signal and the other eye sending a relaxed state. In
> this case the brain has a hard time determining the overriding one,
> but when the relaxed state was predominent I sensed that the image
> was actually far away and huge instead of a few inches away and
> small. It is quite breathtaking when this happens!
> 
> This is all very similiar (and might shed light to 3-D perception)
> to a paper that studied the effect of distance and television
> screen sizes had on the perception of overall size. From what I
> remember reading, it seems that it is not only simple geometry but
> also involves other psychological and physiological factors.
> 
> Gabriel


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