Re: Depth reconstruction in freeviewed images

[P3D Jim Crowell <crowell@xxxxxxxxxxxxxxx>]

At 8:48 AM -0800 1/29/97, P3D Dr. George A. Themelis wrote:
>
>I  know this has been discussed in great length in the past, but I think it
>is due for a new round of comments.  My specific question is, how does the
>mismatch of focal lengths affect reconstructed depth?  In particular, what
>effect does the use of significantly longer FLs (generally the case of
>freeviewing or in projection while sitting way back) has on reconstructed
>depth?  I was under the impression that the z-dimension was stretched.
>That's why portraits look terrible when viewed with longer FLs (projection,
>etc.)  Paul's comments seem to imply that very significant mismatch leads
>to flattening.  Is that because we cannot see the deviation any more?
>What's is going on?
>

Forget ye not that in free-viewing the lens of your eye focuses at the
distance of the image, whereas in a lensed viewer or in projection it's
focused far away.  Assuming you're under the age of 45 or so, anyway :-).
That tends to make free-viewed images look smaller...

-Jim C.

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



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