Re: Computer graphics

[T3D Marvin Jones <72657.3276@xxxxxxxxxxxxxx>]

> Have you actually tried it?  The image is scanned into a perfectly planar
> bitmap and "objects" as such do not exist.  With a great deal of effort you
> can mask outline an object and cut it to its own layer, but then you must
> re-create what was hiding behind the object, sometimes you can borrow
> (clone) from the other image.  That works, though is extremely painstaking,
> for flat objects; but an object viewed obliquely already has a continuously
> varying parallax change, which you decide to alter subtly!  Good luck!

This seems to be a very difficult concept for people who don't work in computer
graphics, and sometimes even for people who do. The topic of computer programs
for automatically converting 2D to 3D has come up several times on the main
list, and I've always tried to make the point that to a computer, a graphic is
just a succession of vari-colored pixels all in a row, and it cannot tell where
a human leaves off and the tree behind him/her begins. I'm always argued down by
people who think that all you have to do is tell the computer what a person
looks like and it will then be able to pick one out of any picture it's fed, and
separate that person perfectly from anything else in the picture. It's largely a
misinterpretation of things like the colorization of movies, in which a computer
can be "shown" a block of similarly-shaded pixels in one frame, and then locate
the same shape in other frames, even if it moves slightly between them. But the
computer doesn't know that the bunch of pixels is John Wayne's shirt, only that
it's a blob of similarly-colored pixels.

Making 3D conversions from 2D images is becoming a viable computer art form, but
as you indicate, it ain't easy! Lincoln Kamm is an expert in the medium, and he
tells me that he can easily spend 60 to 100 hours in constructing a "second-eye
view" from a flat photo.


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