T3D Viewing disparity

["OLE HANSEN" <olejohan@xxxxxxxxxx>]

John Slivon - frogs@xxxxxxxxxx - wrote:
>....I have recently learned how to view stereo pairs using the crossed
> eyes method. I have noticed that when viewed cross-eyed, the stereo
> image appears to be about 60% of the size of either image of the pair....
> Am I just screwed up or is there some "scientific" explanation worthy
> of tech-3D for this?

Gabriel Jacob - jacob@xxxxxxxxxxxxxx - wrote:
> For example, if you have a left and right image stereopair not mounted,
> put them side by side and freeview them crosseyed. They will look
> slightly smaller. Now separate the images and continue to freeview
> them. You'll notice the fused image get progessively smaller. 
> Bringing them back closer together will make them progressively larger
> till they are side by side. Overlapping them, and assuming you could
> still freeview them, you'd reach a unity factor....
> Now separating them further so that your now parallel freeviewing, the
> image will get progressively smaller (instead of larger as in the case
> of crossviewing).

Gabriels description of the phenomemum is good and to the point, but it
does not explain the phenomenum. The reason is, that nobody knows how the
signals from the two eyes are combined in the brain to form the "pictures"
we see, and therefore nobody can give an explanation of the change of size
you see. As you dont change your viewing distance, the two pictures on the
retinas does not change size, but the "picture" you see, does change size.
Quiete intriquing little problem :)
regards
Ole Hansen - olejohan@xxxxxxxxxx




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