Re: SAY YES TO "PSEUDO"!

[P3D Jim Crowell <crowell@xxxxxxxxxxxxxxx>]

At 10:34 AM -0800 2/4/97, P3D  Dave Worrell wrote:
>
>Most of us have seen face sculptures that appear normal when viewed
>"straight on" but are actually concave - but you can't tell till you look
>from an angle. The brain doesn't expect a concave face ... depth clues
>alone are not enough to convince it. I've had similar problems
>interpreting views of lunar craters.
>

There are some nice examples of this in the Haunted House at Disneyland...

Actually, that's a case of depth or shape cues being in conflict.  Your
brain's shape-from-shading algorithm incorporates an assumption that light
usually comes from above & tends to interpret a concavity lit from below as
a convexity.

-Jim C.

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



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