Mail
NEW

Perceived size and location when freeviewing

Perceived size of 3D image

The perceived size when freeviewing could depend if one does parallel or crossed viewing.

For parallel viewing the 3D image's stereo window looks to be at the distance where the stereo pair is presented

The pictures are not allowed to be larger than the eye-separation.
For crossed viewing the 3D image's stereo window looks (at least for me as a former beginner in perceiving crossed viewing) to be smaller than the pictures and closer (at the convergence [3D image] distance) to the viewer (even though the FoV of the picture is the same):

3D image (convergence) distance = eye separation * viewing distance/(picture width+eye separation)

The advantage with crossed viewing is that one can use larger pictures than the eye-separation and thus increasing the resolution/detail. The crossed view 3D image, perceived smaller when using same picture size as with parallel, will thus have a perceived higher resolution than the parallel 3D image; it looks more crisp.

Perceived location of 3D image

Crossed viewing

That the 3D imagine is perceived smaller and closer by, might tells us that convergence is a (weak) depth clue:

A lot of beginning cross-viewers report this. When the eyes are converged, it is as if you are looking close by, so what you see is perceived to be small. After a while even those, who report this, don't notice it any more.

I can understand that when getting more used to crossed viewing that one starts to perceive the small 3D image as larger and migrating to the screen location (due to unlinking convergence from distance). But does this have infleunce on the perceived resolution?

When I get myself more experience with crossed viewing (I saw the 3D image at the convergence distance [Oct. 2009]), I will tell in the future. The 3D image is now (status Dec. 2009) already less obvious at the convergence distance.

Parallel viewing

I have no idea anymore what I experienced when doing for the first time parallel viewing; did I see the 3D image behind the screen distance? I see it now at more or less the screen distance. Any feedback from people just getting used to parallel viewing, is welcome.

To get an impression that the perceived 3D image is behind the screen, try the following:

Have a parallel pair for free viewing (furthest object separation should be equal or smaller than the eye separation: say 6 cm) printed close to the top of a piece of paper. Now try to put your finger in the perceived 3D image, as long as the finger is fully visible, the position of the finger is behind the piece of paper As soon as the finger is hidden by the piece of paper, the perceived distance collapsed (interposition cue)

Disclaimer and Copyright

Home

Mail

Major content related changes: April 17, 2005