Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss

How to view Superbowl 3-D

3 views
Skip to first unread message

Scot E Wilcoxon

unread,
Jan 23, 1989, 1:02:50 AM1/23/89
to
I don't care for the Diet version of Coke, so I don't have
the "official" 3-D glasses. Nevertheless, I taped the
Superbowl halftime show in case it was worth later getting
the glasses. I found the 3-D effect can be viewed from
the tape (SP speed) as well as live.

All I knew of the glasses was what was shown on TV, with
an almost clear left lens and a dark right lens. I
suspected the right lens was either polarized or was
creating an interference pattern (perhaps both), as
the image was supposed to look good without glasses.

While watching the show live, I found the 3-D can be
seen by looking with the right eye through a narrow slit.
The left eye should be uncovered. The slit was about as
far from the eye as a pair of glasses (I wear glasses,
and I simply had the slit on my right lens).

When looking only through the right eye, the slit should
be narrow enough to cause any TV image to have a series
of narrow horizontal bands. The bands look to me like
an interference pattern, so they are an optical effect
of the small slit. A single slit works if it happens
to cover most of the TV image.

With a little experimentation later with the taped
image, I found three objects which work better than
the slit between two fingers.

1. Tape together two large nails. They are not exactly
straight, and can be taped together with a very small
slit between them. This is awkward, but is useful for
experimenting with small slits. (The same effect could
probably be done with flat-edged calipers)

2. Take a small piece of window screen (six inch
diameter). Fold several times. I used three folds
for a pie-shaped piece with eight layers.

3. Take a 1.5 inch by 2 inch Post-It note. (Yes, I
used a 3M Post-It for 3-D) Place on suitable surface
and with a razor blade or utility knife cut many
parallel slits. I made them about 1/16 inch apart,
although closer together would probably work better.
Put them as close together as you can..you can keep
making them until you find the right dimensions.

I prefer Number 3, the 3-D Post-It. I just stick it
on the lens of my right eye, but I sometimes have to
wriggle it a bit to make the slits open up just right.

Number 2, the screen filter, seems to work with the
least adjustment. Photographers might try a star
filter. Nylon or woven fabric might also work.

Anyone have a diffraction grating handy? I suspect
a dark filter over a diffraction grating might work.

How about one dark polarized lens?

As you might expect, the animated backgrounds and
closeups have the most extreme 3-D effects. The
planet/star background and rotating cards are my
favorites for testing.
--
Scot E. Wilcoxon sew...@DataPg.MN.ORG {amdahl|hpda}!bungia!datapg!sewilco
Data Progress UNIX masts & rigging +1 612-825-2607 uunet!datapg!sewilco
I'm just reversing entropy while waiting for the Big Crunch.

Vidiot

unread,
Jan 23, 1989, 8:02:58 PM1/23/89
to
In article <32...@datapg.MN.ORG> sew...@DataPg.MN.ORG (Scot E Wilcoxon) writes:
<I don't care for the Diet version of Coke, so I don't have
<the "official" 3-D glasses. Nevertheless, I taped the
<Superbowl halftime show in case it was worth later getting
<the glasses. I found the 3-D effect can be viewed from
<the tape (SP speed) as well as live.
<
[...lots deleted ...]

First off you didn't have to buy just Diet Coke. It could have been any of
the Coke products.

Secondly, the effect works by fooling the brain. The lenses are not polarized,
just one darker than the other. The darker lens causes the image to be
delayed in the brain, causing the 3D effect. Notice how the stuff moved
from right to left. That was part of it.

I wouldn't be surprised if a neutral density filter would also to the job.
--
harvard-\ att--\
Vidiot ucbvax!uwvax!astroatc!nicmad!brown
rutgers-/ decvax--/
ARPA/INTERNET: brown%nicma...@spool.cs.wisc.edu

-=Stone Soup=-

unread,
Jan 23, 1989, 9:44:07 PM1/23/89
to
From article <32...@datapg.MN.ORG>, by sew...@datapg.MN.ORG (Scot E Wilcoxon):
*8-) --> I don't care for the Diet version of Coke, so I don't have
*8-) --> the "official" 3-D glasses. Nevertheless, I taped the
*8-) --> Superbowl halftime show in case it was worth later getting
*8-) --> the glasses. I found the 3-D effect can be viewed from
*8-) --> the tape (SP speed) as well as live.
*8-) -->
*8-) --> All I knew of the glasses was what was shown on TV, with
*8-) --> an almost clear left lens and a dark right lens. I
*8-) --> suspected the right lens was either polarized or was
*8-) --> creating an interference pattern (perhaps both), as
*8-) --> the image was supposed to look good without glasses.
*8-) -->
*8-) --> While watching the show live, I found the 3-D can be
*8-) --> seen by looking with the right eye through a narrow slit.
*8-) --> The left eye should be uncovered. The slit was about as
*8-) --> far from the eye as a pair of glasses (I wear glasses,
*8-) --> and I simply had the slit on my right lens).
*8-) -->
*8-) --> When looking only through the right eye, the slit should
*8-) --> be narrow enough to cause any TV image to have a series
*8-) --> of narrow horizontal bands. The bands look to me like
*8-) --> an interference pattern, so they are an optical effect
*8-) --> of the small slit. A single slit works if it happens
*8-) --> to cover most of the TV image.
*8-) -->
*8-) --> With a little experimentation later with the taped
*8-) --> image, I found three objects which work better than
*8-) --> the slit between two fingers.
*8-) -->
*8-) --> 1. Tape together two large nails. They are not exactly
*8-) --> straight, and can be taped together with a very small
*8-) --> slit between them. This is awkward, but is useful for
*8-) --> experimenting with small slits. (The same effect could
*8-) --> probably be done with flat-edged calipers)
*8-) -->
*8-) --> 2. Take a small piece of window screen (six inch
*8-) --> diameter). Fold several times. I used three folds
*8-) --> for a pie-shaped piece with eight layers.
*8-) -->
*8-) --> 3. Take a 1.5 inch by 2 inch Post-It note. (Yes, I
*8-) --> used a 3M Post-It for 3-D) Place on suitable surface
*8-) --> and with a razor blade or utility knife cut many
*8-) --> parallel slits. I made them about 1/16 inch apart,
*8-) --> although closer together would probably work better.
*8-) --> Put them as close together as you can..you can keep
*8-) --> making them until you find the right dimensions.
*8-) -->
*8-) --> I prefer Number 3, the 3-D Post-It. I just stick it
*8-) --> on the lens of my right eye, but I sometimes have to
*8-) --> wriggle it a bit to make the slits open up just right.
*8-) -->
*8-) --> Number 2, the screen filter, seems to work with the
*8-) --> least adjustment. Photographers might try a star
*8-) --> filter. Nylon or woven fabric might also work.
*8-) -->
*8-) --> Anyone have a diffraction grating handy? I suspect
*8-) --> a dark filter over a diffraction grating might work.
*8-) -->
*8-) --> How about one dark polarized lens?
*8-) -->
*8-) --> As you might expect, the animated backgrounds and
*8-) --> closeups have the most extreme 3-D effects. The
*8-) --> planet/star background and rotating cards are my
*8-) --> favorites for testing.
*8-) --> --
*8-) --> Scot E. Wilcoxon sew...@DataPg.MN.ORG {amdahl|hpda}!bungia!datapg!sewilco
*8-) --> Data Progress UNIX masts & rigging +1 612-825-2607 uunet!datapg!sewilco
*8-) --> I'm just reversing entropy while waiting for the Big Crunch.


Scot, Scot, Scot! What a trickster you are! My God! By the time
anyone takes all the time to do what you suggest they will dicover
it is much easier to just buy the damn pop and give it away. Keep
the glasses though!


Botch -=Do yourselves a favor, buy the pop=- Casually


--
"We're not talking cute little ET's here either, Doctor."

-- Colonel Ironhorse (War of the Worlds)

Botch Casually rek...@andy.bgsu.edu

Robert allen Jung

unread,
Jan 24, 1989, 12:17:40 PM1/24/89
to
In article <36...@nicmad.UUCP> br...@nicmad.UUCP (Vidiot) writes:
> [Lots on how to make 3D glasses deleted]

>
>First off you didn't have to buy just Diet Coke. It could have been any of
>the Coke products.

Just out of curiousity, I couldn't find the glasses _anywhere_ (L.A. area).

Was there a distribution problem, or are my local 7-11's screwed up?

--R.J.
B-)

P.S. Is this message even reaching the rest of the free world?

:::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::::
___ ______ __ __
/ _ \ | ____ \ || || Call the O-MAYER V BBS! (213) 732-0229
|| || || || || \\ //
||_|| || || || \\// As friendly as you can get!
\___/ || || || \/ * Discussions on anything under the sun!
* 20 Mbytes of storage -- Spectre, PC Ditto, more!
* 1200/2400 baud! 24 hours! PC Pursuit-able!

Craig Good: Central Marin Home for the Bewildered

unread,
Jan 24, 1989, 4:21:58 PM1/24/89
to
In article <32...@datapg.MN.ORG> sew...@DataPg.MN.ORG (Scot E Wilcoxon) writes:
:I don't care for the Diet version of Coke, so I don't have

:the "official" 3-D glasses. Nevertheless, I taped the
:Superbowl halftime show in case it was worth later getting
:the glasses. I found the 3-D effect can be viewed from
:the tape (SP speed) as well as live.
:
:All I knew of the glasses was what was shown on TV, with
:an almost clear left lens and a dark right lens. I
:suspected the right lens was either polarized or was
:creating an interference pattern (perhaps both), as
:the image was supposed to look good without glasses.
:

Your empiricism is good, but you nicked yourself on Occam's Razor. It
turns out the system is diabolically simple. Putting a dark lens
over your right eye causes you to percieve the image slightly later
than with the left eye. No, the filter doesn't slow down the light.
There is some artifact which I don't understand at work here. My suspicion
is that rods are slower than cones. Whatever the reason, it works. So
the whole trick to broadcasting this kind of "3-D" is to move the camera
right-to-left. That moves the image left-to-right. Your right eye sees
the image later, after a perspective shift, and presto!

I don't know how these guys sold it as a licensed product since you
can't very well patent a camera move, and the glasses are simply one
clear lens and one grey one. Since it's based on motion artifacts there
are annoying things about motion artifacts in the image. Pretty darn
clever, though.


--Craig
...{ucbvax,sun}!pixar!good

John Sparks

unread,
Jan 25, 1989, 9:33:41 AM1/25/89
to
In article <32...@datapg.MN.ORG>, sew...@datapg.MN.ORG (Scot E Wilcoxon) writes:
> While watching the show live, I found the 3-D can be
> seen by looking with the right eye through a narrow slit.
> The left eye should be uncovered. The slit was about as
> far from the eye as a pair of glasses (I wear glasses,
> and I simply had the slit on my right lens).
>
> 1. Tape together two large nails. They are not exactly
> straight, and can be taped together with a very small
> slit between them. This is awkward, but is useful for
> experimenting with small slits. (The same effect could
> probably be done with flat-edged calipers)
>
> 2. Take a small piece of window screen (six inch
> diameter). Fold several times. I used three folds
> for a pie-shaped piece with eight layers.
>
> 3. Take a 1.5 inch by 2 inch Post-It note. (Yes, I
> used a 3M Post-It for 3-D) Place on suitable surface
> and with a razor blade or utility knife cut many
> parallel slits. I made them about 1/16 inch apart,
> although closer together would probably work better.
> Put them as close together as you can..you can keep
> making them until you find the right dimensions.
>
> I prefer Number 3, the 3-D Post-It. I just stick it
> on the lens of my right eye, but I sometimes have to
> wriggle it a bit to make the slits open up just right.
>
> Number 2, the screen filter, seems to work with the
> least adjustment. Photographers might try a star
> filter. Nylon or woven fabric might also work.
>
> Anyone have a diffraction grating handy? I suspect
> a dark filter over a diffraction grating might work.
>

Why go thru all that trouble? Use a dark pair of sunglasses over one eye
leave the other eye uncovered.


As someone posted in rec.video, the effect seems to happen becuase dark
images register later in the brain than light images. this timing difference
seems to create a 3D effect. There can be no polarization on a video screen
that I know of. How can you polarize the electron beam with a video signal??

Besides I thought the 3d effect fell flat (pun intended) the only part of
the show that looked 3d to me was the computer graphics of the planets and
stars. I noticed that the faster an object moved horizontally on the screen
the 'closer' it looked. no motion, no 3d. This is why most of the live action
did not seem 3d. the camera men where mostly stationary. And the performers
would move various part of themselves (such as the girls twirling batons) and
those parts would seem to jump out while the rest of them seemed flat. This
just sent confusing signals to my already confused mind, making the whole
thing a bust. Also, I am pretty sure there was no special equipment involved
in filming the 3d process. you can watch other shows with the glasses on
and get the same 3d effect when something moves horizontally on the screen.

_______________________________________________________________________________

John Sparks // Amiga | corpane : sparks@corpane
a.k.a \X/ UUCP | blitter : john@blitter (preferred; path below)
RedHawk ~~~~~~~~~~~~| {rutgers|uunet}!ukma!corpane!disk!blitter!john
D.R.A.G.O.N.| >> call D.I.S.K. @ 502/968-5401 thru -5406 <<
Ye Quote:
Build something that even a fool can use, and only a fool will want to
use it.
-- C. Shaw.
_______________________________________________________________________________

Kati Strong

unread,
Jan 25, 1989, 10:10:02 AM1/25/89
to

>First off you didn't have to buy just Diet Coke. It could have been any of
>the Coke products.
>
>Secondly, the effect works by fooling the brain. The lenses are not polarized,
>just one darker than the other. The darker lens causes the image to be
>delayed in the brain, causing the 3D effect. Notice how the stuff moved
>from right to left. That was part of it.
>
>I wouldn't be surprised if a neutral density filter would also to the job.
>--
> harvard-\ att--\
>Vidiot ucbvax!uwvax!astroatc!nicmad!brown

1st, sorry for the awful space at the top of this article but I don't know vi
(our editor) very well.

You are right about the dark lens causing the image to have a 3D effect. We
found that we could hold an ordinary pair of sunglasses over the right eye
only, leaving the left eye sight line clear, and see the 3D effect very
well.

-------------------------------------------------------------------------------
Kati Strong | DISCLAIMER: Does anyone *ever* agree
| With me?

-------------------------------------------------------------------------------
UUCP:{amdcad,decwrl,hplabs,oliveb,pur-ee,qantel}!intelca!mipos3!cadev4!kstrong
ARPA:kstrong%cadev4.i...@relay.cs.net

Ronald Buttiglieri

unread,
Jan 25, 1989, 5:27:00 PM1/25/89
to
In article <30...@pixar.UUCP> go...@pixar.uucp (Craig Good: Central Marin Home for the Bewildered) writes:
>In article <32...@datapg.MN.ORG> sew...@DataPg.MN.ORG (Scot E Wilcoxon) writes:
>:I don't care for the Diet version of Coke, so I don't have
>:the "official" 3-D glasses. Nevertheless, I taped the ....

>:All I knew of the glasses was what was shown on TV, with
>:an almost clear left lens and a dark right lens. I ....

>:
>
>Your empiricism is good, but you nicked yourself on Occam's Razor. It
>turns out the system is diabolically simple. Putting a dark lens
>....

>I don't know how these guys sold it as a licensed product since you
>can't very well patent a camera move, and the glasses are simply one
>clear lens and one grey one. Since it's based on motion artifacts there
>are annoying things about motion artifacts in the image. Pretty darn
>clever, though.
>
>
In the interest of science (always wanted to say that) and my own
insatiable curiosity, I referred back to Popular Science June '88 issue
that had an article on 3-D TV. Several methods of 3-D are described,
including the technique (very accurately described in prev. postings)
used at-the-half. This was originally supposed to be used on the
last show from last-season's _Moonlighting_. (I assume the writer's
strike stopped that from happening)

With reference to the comment about "licensed product", in the interview
with the president of Nuoptix Inc., he explained that their company
also developed a new "film-to-tape process" by which they can get
60+ frames per second rather than the standard 24 fps. This explains
why the commercial is so crisp in detail. I believe this "aids" in the
3-D effect because the eye receives more (faster rate) information, more
like real-life. This is *probably* what they license(?).

With (or without, just use a dark lens on the "trailing eye") the 3-D
glasses, other TV shows can produce a similar effect. Try it. Again,
the horizontal motion is the real key.

One other thing suggested in the article was to look at a 'snow-filled'
screen (UHF non-channel?) with the glasses for an interresting effect.
(just don't let your neighbors see you, they'll think you've flipped)

And, of course, there's the: " Wow! With these glasses on, EVERYTHING
looks 3-D! Look at my HAND! WOW!.." :^)

Ron

Bob Calbridge

unread,
Jan 26, 1989, 1:55:42 PM1/26/89
to
In article <30...@pixar.UUCP>, go...@pixar.uucp (Craig Good: Central Marin Home for the Bewildered) writes:
[deleted some other stuff found laying around in here]


> I don't know how these guys sold it as a licensed product since you
> can't very well patent a camera move, and the glasses are simply one
> clear lens and one grey one. Since it's based on motion artifacts there
> are annoying things about motion artifacts in the image. Pretty darn
> clever, though.

I can't see a camera of any perceivable mass being moved fast enought to
work within the speeds need to produce a new frame every sixtieth of a
second. Conceivably what they did was have two cameras and electronically
switch between the two somehow. This might be able to be licensed.

Marc J Balcer

unread,
Jan 26, 1989, 5:56:39 PM1/26/89
to
In article <36...@nicmad.UUCP> br...@nicmad.UUCP (Vidiot) writes:
>I wouldn't be surprised if a neutral density filter would also to the job.

Anything dark enough will work. I used a pair of sunglasses, holding
one of the lenses over my right eye. The dark lens causes the image
to reach the right eye just a bit later than the left eye. Coupled
with motion of the image, your brain interprets this as 3-D.

Did you notice how the commercial and the pre-recorded bits seemed to
have a better 3-D effect than other parts of the halftime show?
Those parts had large objects moving at a relatively constant speed
across the screen.

In fact, any TV picture with enough contrast and large-object motion
will produce the same effect. Try your "glasses" the next time you
watch any TV program (sports and shows with lots of "action" give the
best effect).

I have a feeling that since this technology is so simple, we'll be
seeing lots more of it.
---------------------------------------------------------------------------
Marc J. Balcer
[bal...@gypsy.siemens.com]
Siemens Research Center, 755 College Road East, Princeton, NJ 08540
(609) 734-6531
---------------------------------------------------------------------------

Go ahead. Make my day.

unread,
Jan 26, 1989, 9:30:31 PM1/26/89
to
In article <4115381...@apollo.COM> ro...@apollo.COM (Ronald Buttiglieri) writes:
:
:... This was originally supposed to be used on the

:last show from last-season's _Moonlighting_. (I assume the writer's
:strike stopped that from happening)

You assume correctly.

:With reference to the comment about "licensed product", in the interview


:with the president of Nuoptix Inc., he explained that their company
:also developed a new "film-to-tape process" by which they can get
: 60+ frames per second rather than the standard 24 fps. This explains
:why the commercial is so crisp in detail. I believe this "aids" in the
:3-D effect because the eye receives more (faster rate) information, more
:like real-life. This is *probably* what they license(?).

Video is 30 frames per second, and 60 fields per second. A complete frame
is composed of two fields, each of which has alternate scan lines. So it's
like you see the odd lines, then the even lines, each frame. Sound film
is 24 frames per second. Film-to-tape transfers do what is called a
"3:2 pulldown" to correct for the difference in frame rates. There is
nothing special about this, either. The reason the commercial looked
so "crisp" was that it was shot and produced on video -- and very good
video at that. That means that there were no motion artifacts from a
film-to-tape transfer to worry about. Anyway, other than just staying
pure video there's nothing they can do to get information to you at a
faster rate. (On the other hand, ShowScan, a film process, *can* do that.
And it's a lot better than 3-D.)


--Craig
...{ucbvax,sun}!pixar!good

Mike McDonnell

unread,
Jan 27, 1989, 11:20:15 AM1/27/89
to

The effect used to do the 3D for the Superbowl is called the "Purkinje
phenomenon" and has been known for a long, long time. It is one of the
easiest "proofs" that the eye is an active imaging device that
interprets input and doesn't just decode it. As the light level goes
down, the integration time of the eye goes up and a moving image will
therefore be perceived as lagging its true optical location on the
retina by an amount that depends on the overall light level. This is a
neural effect, not an optical effect.

As far as use of the Purkinje phenomenon in entertainment, I went to a
light show at a planetarium in 1976 where the "Heavy Water Light Show
Company" presented the show "Quantum Reflections". Patrons were issued
"heavy water goggles" consisting of dark plastic film with a hole
punched out for the left eye. Effects included a ferris wheel revolving
through the top of the dome. Quite spectacular, particularly if you
were stoned...
--
Mike McDonnell at the U.S. Army Engineer Topographic Laboratories, Bldg. 2592
Fort Belvoir, VA 22060-5546 TEL:(202)355-2716 NET: mi...@ai.etl.army.mil

Matthew Turk

unread,
Jan 27, 1989, 3:40:15 PM1/27/89
to
In article <2...@corpane.UUCP>, spa...@corpane.UUCP (John Sparks) writes:
> ..... And the performers

> would move various part of themselves (such as the girls twirling batons) and
> those parts would seem to jump out while the rest of them seemed flat. This
> just sent confusing signals to my already confused mind, making the whole
> thing a bust. Also, I am pretty sure there was no special equipment involved...

Well, maybe a little silicon! ;-) (I guess a comment on TV being a
"boob tube" would be a little out of hand here, huh?)

James Mork

unread,
Jan 27, 1989, 4:09:22 PM1/27/89
to

I have seen various arguments about how the three-d effect is
achieved... would someone correct me if I'm wrong...


The objects are broadcast with r........b
extra colors on the edges (blue r. .b
and red... I think) A square r. .b
would then look like this -------> r........b

The glasses are a blue filter
and a red filter-> ---(r)-(b)---

Each side of the square gets
filtered out by one eye seeing
through a red or blue filter.

One eye sees --------------------> ........b
. .b
. .b
........b

The other sees ------------------> r........
r. .
r. .
r........

These conflicting shifts are
(sorta) combined by the brain
into a sense of perspective...
A fake feeling of binocular
vision...


Confirm or Deny?


--
UUCP Bitnet Internet
uunet!ndsuvax!numork numork@ndsuvax num...@plains.nodak.edu


#! rnews

Pixar: Where quality isn't just a word, it's a noun!

unread,
Jan 28, 1989, 6:41:01 PM1/28/89
to
In article <69...@killer.DALLAS.TX.US> bo...@killer.DALLAS.TX.US (Bob Calbridge) writes:

:In article <30...@pixar.UUCP>, go...@pixar.uucp (Craig Good: Central Marin Home for the Bewildered) writes:
:[deleted some other stuff found laying around in here]
:
:> I don't know how these guys sold it as a licensed product since you
:> can't very well patent a camera move,...
:
:I can't see a camera of any perceivable mass being moved fast enought to

:work within the speeds need to produce a new frame every sixtieth of a
:second. Conceivably what they did was have two cameras and electronically
:switch between the two somehow. This might be able to be licensed.

Ok, I finally heard the poop on their "new" film-to-tape system. They
shoot at 60 frames per second (just like ShowScan) and transfer so that
each new video field is sampling a new film frame. That's why the video
looked so darn good -- it's about as good an image-capture sytem for
video as exists today (since TV cameras are still trying to catch up
to film).

I'm not sure what was meant by "moving a camera fast enough to make a
new frame every sixtieth of a second", so I'll address the two most
obvious. First, and this is the trickiest one, is the business of
moving the film in the camera quickly enough for that frame rate. But
that is now a very mature technology (slow-motion camera speeds have only
been around several decades now), at least for 35mm stock. Second, which
is actually moving the camera, is trivial. It doesn't take much movement
to move things so that each frame looks different.

I remain as impressed with their salesmanship as their "technology".


--Craig
...{ucbvax,sun}!pixar!good

John Schultz

unread,
Jan 29, 1989, 5:02:30 PM1/29/89
to
In article <30...@pixar.UUCP> go...@pixar.uucp (Go ahead. Make my day.) writes:
[stuff deleted]
>...there's nothing they can do to get information to you at a

>faster rate. (On the other hand, ShowScan, a film process, *can* do that.
>And it's a lot better than 3-D.)
> --Craig

I saw ShowScan at the Reuben H. Fleet Space theater; it was
incredible to say the least. Some women in front of us were crying
because the view of the mountain ranges was so breathtaking. It
really stimulates the brain. They stated that they couldn't do a
film like Predator in ShowScan as it would be too powerful of an
effect for people with health problems. At 60 frames of new
information a second, very large reels are needed for ShowScan
films. They stated that is would cost on the order of ~$100,000 to
convert a theater to ShowScan. The only change to the screen is to
make the whole front of the theater the screen.
I wonder if they have tried ShowScan in 3D [120 frames/sec, 60 per
eye]. To date, that would be the ultimate...


John Schultz

Alain Fournier

unread,
Jan 30, 1989, 10:28:05 AM1/30/89
to
I indeed suspect the Purkinje effect has something to do with this.
Since Purkinje made a lot of "subtle observations" (to quote R. M. Boynton,
whose book "Human Color Vision" is a must read) about human vision, he described
different effects. The Purkinje shift in particular refers to the shift in
spectral sensitivity that occurs when the eye shifts from cones to rods (this
is probably the effect that Craig Good had in mind when he surmised that this
transition had something to do with the "Super-Bowl" 3D demo). For those
of you in the Bay area, the Exploratorium has a demo of the effect. If memory
serves, there is a pendulum oscillating in a plane perpendicular to the
viewer, and because it's less illuminated on one side it appears to revolve
in a circle (that is there is a component of apparent motion away from the
viewer). I hope Purkinje's descendants get some money from any patent obtained.


Kevin Tubbs

unread,
Jan 30, 1989, 11:22:49 AM1/30/89
to
In article <2...@ai.etl.army.mil> mi...@ai.etl.army.mil (Mike McDonnell) writes:
<
<The effect used to do the 3D for the Superbowl is called the "Purkinje
<phenomenon" and has been known for a long, long time. [...]

<As the light level goes
<down, the integration time of the eye goes up and a moving image will
<therefore be perceived as lagging its true optical location on the
<retina by an amount that depends on the overall light level. This is a
<neural effect, not an optical effect.

A good example of this is waving a flashlight in a dark room. The lighted
end seems "disconnected" from the handle.
--
Kevin Tubbs, 5152 Upson, Cornell University, Ithaca NY, 14853 (607) 255-8703
ke...@calvin.ee.cornell.edu {uunet,rochester}!cornell!calvin!kevin

John B. Nagle

unread,
Jan 30, 1989, 11:55:09 AM1/30/89
to

Clearly the next step after HDTV will have to approach Showscan
resolution. We are also going to need computer displays with that kind
of bandwidth. How much bandwidth is it? Well, a 70mm film frame is
generally considered to be about 6000 by 8000 pixels. So 60fps x
256 levels x 3 colors x 6000 x 8000 = 2.2*10^12 bits/sec, or an
uncompressed data rate of about two terabaud. Hardware with this
kind of speed should be achievable by 1995 or so.

For flight simulators and such, one really needs an image that covers
a hemisphere. What fraction of a sphere is Showscan?

The amount of compute power necessary to generate high-quality
images in real time at these densities will be rather large. If we
take a goal of obtaining the quality of Pixar's "Tin Toy", and want a
hemispherical view, how much compute power will be required, and,
based on projections that progress continues at current rates, when do we
get it?

John Nagle

Charl Phillips

unread,
Feb 1, 1989, 4:16:42 PM2/1/89
to
60 frames per second?!?? Mygawd!

Aren't there any persistence problems?

Charl Phillips
San Diego, CA

Pete Goodeve

unread,
Feb 5, 1989, 5:50:56 AM2/5/89
to

In article <2...@ai.etl.army.mil> mi...@ai.etl.army.mil (Mike McDonnell) writes:

< The effect used to do the 3D for the Superbowl is called the "Purkinje

< phenomenon" and has been known for a long, long time. [...]

and in <890130152...@donnacona.dgp.toronto.edu>
al...@dgp.toronto.edu (Alain Fournier) writes:

< indeed suspect the Purkinje effect has something to do with this.

Interesting... And I thought *I* was the only one who keeps mixing up
those two names...! Actually -- as was pointed out by a couple of other
people -- it is a guy named "Pulfrich" that we have to blame for what was
inflicted on us. As was also correctly pointed out by someone, the
"Purkinje Shift" is the change in *spectral* response as the eye switches
to using rods instead of cones. Ah well.. it's these damn furriners'
fault for having such awkward names... (:-)) (:-)) (:-))

I guess the whole subject has been pretty well worked out by now, anyway,
except that Pepsi have decided to get a bit of mileage out of it.
Have other people seen that commercial? I nearly fell out of my chair
the first time I saw it, and I'm still liable to get fits of giggling
at odd moments... [and *I* never touch anything but Coke Classic...]

-- Pete --

0 new messages