P3D Re: Parallax tech, deviation

[Larry Berlin <lberlin@xxxxxxxxx>]

>Date: Wed, 01 Dec 1999
>From: abram klooswyk <abram.klooswyk@xxxxxx>
>..........
>Since "parallax" is often also used in the sense of the
>linear shift on the stereopicture, it might be good to
>stress that this should be avoided.
>........................
>
>Koo Ferwerda had a degree in astronomy and wrote a thesis on
>an astronomical subject, it was not entirely on right-angled
>triabgles :-). Indeed, parallax is
>> not specific to astronomy
>but it does originate from astronomers, and it seems good to
>stick to their definition.

*****  That's interesting.

>
>Ferwerda again points out in his book "The World of 3-D"
>(see http://www.stereoscopy.com/3d-books) that the parallax
>of a point is the angle, subtended at that point, of the "visual
>lines" from two different (viewing) positions.
>
>"Deviation" is the linear shift Greg mentions, by definition it is
>the difference of the separation of a homologous pair of
>points on the stereophotograph and the separation of a pair
>of very distant or "infinity" homologues.
>
>"Separation" again is the preferred word for the distance
>between left and right "items", to avoid confusion with
>distances in space, e.g. from the stereocamera to an object.
>
>Since we have these three dimensions, it is convenient to
>have accurate terms to avoid getting lost in space...
>


****  Thanks Abram. That was the definition I was looking for.

Larry Berlin

Email: lberlin@xxxxxxxxx
http://3dzine.simplenet.com/