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From: eugene@nas.nasa.gov (Eugene N. Miya)
Newsgroups: comp.graphics
Subject: Re: Psycho Graphics
Message-ID: <1991Feb14.175722.21713@nas.nasa.gov>
Date: 14 Feb 91 17:57:22 GMT
References: <91Feb14.110238est.7256@neat.cs.toronto.edu>
Sender: news@nas.nasa.gov
Reply-To: eugene@wilbur.nas.nasa.gov (Eugene N. Miya)
Organization: NAS Program, NASA Ames Research Center, Moffett Field, CA
Lines: 75

In article <1991Feb12.013754.5320@nas.nasa.gov> eugene@wilbur.nas.nasa.gov
I asked: (to the question about other bases than physics)
>> Pray tell, what other bases would you suggest?

>I wonder if I dare to mention psychophysics. With this logic it is
>probably associated with Donald Duck.
>
>well...here is a *very* simple example called the moon illusion:

Sure, this is acceptable, but it's still got physics. (not just the word.)
I think here my bottom line is:
	It's dependent on your application of imagery.
I acknowledge that generating synthetic images entertaining uses.
That's why I gave the texture mapping example.  For fun, you only need
mimic a cloud.  But for non-entertainment uses of graphics: mapping,
simulation, analysis, we have to go beyond.  I asked for
clarification: what other models?  You have to be careful about
illusions, this is why magic is relegated to entertainment these days.
You can't build a lot of work on illusions (generalization).

In article <91Feb14.110238est.7256@neat.cs.toronto.edu>
mgreen@cs.toronto.edu (Marc Green) writes:
>All this talk of "Psycho Graphics" shows that many computer graphics
>people badly need a basic perception course. Why? Because there is
>very little correlation between physics and perception.

Agreed that graphics people need courses in perception.  This is
why I gave the example "human factors."  Some of our best attended
past local SIGGRAPH meetings have been on topics like color.

>Perception is psychological while images are physical. The
>relationship between the two complicated and not deterministic. For

Music: to use another entertaining example is the same way.
Not to dump too hard, there is an argument for Renaissance imaging teams
to have artists.  I think this is wrong.  You get one artist's perceptions.
That artist really needs to be a perceptual psychologist.  That's not
enough.  DO not misinterpret me.  I do like art, and I do like abstract
art which makes use of lots of illusions, but the application, use,
value is limited.

>The basic fact to remember is that our perceptions are manufactured in
>our heads and depend as much or more on the way our visual systems are
>wired together than by the retinal image.

True.

> It is wasted effort to spend
>time worrying about complicated camera models and the like. For
>example, fancy models of motion blur simply are unnecessary. The real
>question is not how to make computer graphics look like cameras, but

To come to Olli's defense (why I suggested removing the "very little")
people (humans) are involved in systems like flying airplanes and driving
cars where it is useful and important to know these things.  The effort is
not completely wasted.  If we are only going to make cartoons,
this is acceptable.  I suggest a visit sometime to an airline wherein
you should ask if you can sit in a flight simulator cockpit.

Remember: I only asked for other models.  I still get physics.

--e. nobuo miya, NASA Ames Research Center, eugene@orville.nas.nasa.gov
  {uunet,mailrus,other gateways}!ames!eugene
  AMERICA: CHANGE IT OR LOSE IT.
  In the book Land's Polaroid: I think Sam Goldwyn was shown a movie shot
  in 3-D.  Everyone who saw it "had their socks knocked off."  Goldwyn
  walked out it was no biggie to him.  Months later Land, America's
  second most patented inventor, learned that Goldwyn had a glass eye.

  Blinn points out the need to occasionally look at his quality graphics
  using a B&W screen.  This is a good idea.

  We are developing sophisticated color graphics systems for scientific
  visualization.  For better or worst, most of the scientific community is
  male, and 1/6 males have some degree of color blindness.