Re: Ortho Grand Canyon

[P3D Jim Crowell <crowell@xxxxxxxxxxxxxxx>]

At 10:59 PM -0800 1/28/97, P3D  Dr. George A. Themelis wrote:
>Sorry, I don't have to add anything to the subject, but I would like to
>say that I enjoyed Paul's description of how he got hooked into 3d when
>he saw a nice stereo of Grand Canyon:
>
>>The realism of a
>>good Realist image of the Grand Canyon does a wonderful job of making me
>>feel like I am there, which of course is a very powerful experience.  A
>>good hyper of the Grand Canyon is interesting and enjoyable, but I have
>>not seen one that captures that sense of being there.
>

On a bit of a tangent, there's some recent research that bears on this.  A
fellow in Holland looked at how one perceives the size of
computer-generated, non-familiar objects under different viewing
conditions.  The comparison of interest was (1) monocular viewing vs. (2)
binocular viewing, with both eyes getting the same image (analogous to a
very distant object), vs. (3) binocular viewing, with the differences
between the two images being appropriate for a near viewing distance of a
photograph (there are differences, because the slant of the photograph is
slightly different with respect to the lines of sight from the two eyes).

The result was the (2) looked far away the biggest & farthest away & (3)
looked much the smallest & nearest.  So apparently the brain does use the
total absence of disparity between two images as a cue for a large distance
& that makes things look even bigger (& probably in general more realistic)
than they do when viewing a normal photo, even with one eye.

That said, I do tend to prefer hypers of large landscape features & cities.
I think the reason is that as I move around a large object, I tend to build
up a fairly precise 3D model of it in my head, & that model has an almost
tactile quality to it.  That quality is lost in an ortho shot but retained
in a hyperstereo...

-Jim C.

----------------------
Jim Crowell
Division of Biology
216-76
Caltech
Pasadena, CA
(818) 395-8337
jim@xxxxxxxxxxxxxxx



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