[tech-3d] "ortho" digression

[John Toeppen <toeppen@xxxxxxxx>]

abram.klooswyk@xxxxxx wrote:

> orthoscopic:  giving a true flat image without distortion
> (A flat image just isn't what we like :-), but elimination of the
> curvature of field is meant.)

I think that this term was used pertaining to map making and
the process of "orthorectification"  Making it all "right"

Orthographic projection is a drafting technique for perspective
rendering that does not use vanishing points.  This "flattening" 
of an image is similar to the use of very long focal length lenses.
Near objects appear no larger than far ones.

Stereo pairs made using long lenses will be affected by this effect.
The same effect may be had by cropping a large high resolution scan
taken
using a normal (50mm on a 35mm camera).  Highly curved image fields
taken
with a 28mm only mux (digially compile)well if the cameras are pointed
in 
the same direction.  "Orthostereoscopic" is a good term but remember
that
 it also refers to accomodation and field of view - not just the
apparent angular proportions.

John Toeppen
http://members.home.com/holographics/

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