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From: Andrew Coppin
Subject: WIP: Sterograms of a cube!
Date: 4 Jan 2003 09:04:15
Message: <3e16e9df@news.povray.org>
Hey folks!

It was about June last year that I discovered how Single Image Sterograms
work (aka "magic eye pictures"). Since then I've done no end of text-based
ones using Notepad. (I had no idea you could do it with plain text as well
as images! That's how I found out how they work by the way...) If you're one
of those people who can't see these images, you probably won't be very
excited by this thread!

I'll reply to my own post in a mo with some example images attached. The
images are fairly big (800x600), and unfortunately I can't use lossy
compression, because it messes up the 3D effect (which IS the entire point
of the post!)

Stand by...
Andrew.


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From: Andrew Coppin
Subject: Re: Sterogram #1 (~320KB)
Date: 4 Jan 2003 09:09:53
Message: <3e16eb31@news.povray.org>
Here is the first example... The 3D effect is a little extreme.

Andrew.


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Attachments:
Download 'Cube1-Diffuse2.png' (321 KB)

Preview of image 'Cube1-Diffuse2.png'
Cube1-Diffuse2.png


 

From: Andrew Coppin
Subject: Re: Sterogram #2 (~209KB)
Date: 4 Jan 2003 09:19:22
Message: <3e16ed6a@news.povray.org>
Here is the second one... The entire image has a very slight overall
curvature that I don't know how to get rid of. The 3D depth is less extreme
and more realistic that the other example.

Andrew.

PS. Forgot to say... I'm posting a thread in povray.advanced-users about
this...


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Attachments:
Download 'SIPS3-Real-Small.png' (210 KB)

Preview of image 'SIPS3-Real-Small.png'
SIPS3-Real-Small.png


 

From: Sir Charles W  Shults III
Subject: Re: Sterogram #2 (~209KB)
Date: 4 Jan 2003 11:05:58
Message: <3e170666@news.povray.org>
I think you use the isomorphic camera for that.

Cheers!

Chip Shults
My robotics, space and CGI web page - http://home.cfl.rr.com/aichip


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From: Apache
Subject: Re: Sterogram #2 (~209KB)
Date: 4 Jan 2003 12:22:32
Message: <3e171858@news.povray.org>
move the camera ver far away and lower the angle. A smaller angle value
zooms the camera, so there will be less perspective.


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From: Bill DeWitt
Subject: Re: Sterogram #1 (~320KB)
Date: 4 Jan 2003 13:55:22
Message: <3e172e1a$1@news.povray.org>
"Andrew Coppin" <orp### [at] btinternetcom> wrote in message
news:3e16eb31@news.povray.org...
> Here is the first example... The 3D effect is a little extreme.

    They're fun in crossed eye viewing too.


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From: Jaap Frank
Subject: Re: Sterograms of a cube!
Date: 4 Jan 2003 22:22:10
Message: <3e17a4e2@news.povray.org>
"Andrew Coppin" <orp### [at] btinternetcom> wrote in message
news:3e16f133@news.povray.org...
> I've posted a couple of images - see povray.binaries.images.
>
> It was about June time last year that I discovered how Single Image
> Sterograms ("magic eye pictures") work. You can actually make 'em out of
> plain ordinary text! I've done so with Notepad many times...
> <snip>
 > The basic idea is to have similar-but-no-identical repartitions in the
> image. If you take a cube and duplicate it across the screen, then owing to
> the perspective effect, you see each cube from a slightly different angle.
> If you view the thing as a sterogram (i.e., look at it cross-eyed), you get
> a 3D effect.
>
> However...
>
> The 3D bit comes out backwards! (That is, the front-most part is at the
> back, with the back edges at the front. It looks really odd!)

Your are mixing up two different Stereograms systems.
1. "magic eye pictures"
    For this you must stare at the picture, that will say you look behind the
picture.
    If you wait, your eyes look at different pictures. Your right eye takes an
object
    to the right of that of your left eye. Your brain makes a 3D image off these
    slightly different pictures.
    Exaggerated this is what you do:

    Left                                 |                               Right
    Object                            |                               Object
                        Position       |            Position
                        Left eye       |            Right eye

    If the left and right object are placed in the same orientation (not rotated
to
    each other), then your left eye sees the right side of the object a bit and
your
    right eye sees the left side of the object a bit.
    This is just the wrong way around. Your right eye should see a bit of the
right
    side of the object and your left eye a bit from the left side.

2. Crossing eye method.
    By crossing your eyes you look before the picture and your left eye now
    looks at the right object and your right eye looks at the left object.
    Exaggerated this is what you do:
        Left                               |                                 Right
    Object                               |                                Object
                        Position          |         Position
                        Right eye        |         Left eye

    This is precisely what a 3D picture should be.
    Now you can understand that the "magic eye pictures" were flipped
    forward - backwards. Your eyes saw the wrong side of the object.
    By the way:
    The strain for your eyes is the wrong focusing and your brain must be
    learned to do this. My experience is that young people do have
    difficulties with the crossing eyes method. Older people strangely can
    learn it faster.

Tip: Put the identical objects at a considerable distance and use a camera
        with an angle of about 6 - 8 degrees, else the effect is exaggerated.

<snip>
>
> Thanks!
> Andrew.
>
> PS. Can anyone here see sterograms btw? Kinda pointless if you can't :P

I've made even videos for the crossing eye method and can now look at
them for hours without effort. Indoctrination of the brain works!!

Greetings,

Jaap Frank

PS: I've attached an example. This is a part of a hemoglobine protein chain.
      Happy crossing your eyes.








--------------------------------------------------------------------------------


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Attachments:
Download 'Hemoglob1.png' (238 KB)

Preview of image 'Hemoglob1.png'
Hemoglob1.png


 

From: Andrew Coppin
Subject: Re: Sterograms of a cube!
Date: 5 Jan 2003 06:41:58
Message: <3e181a06@news.povray.org>
> Your are mixing up two different Stereograms systems.
> 1. "magic eye pictures"
>     For this you must stare at the picture, that will say you look behind
the
> picture.
>     If you wait, your eyes look at different pictures. Your right eye
takes an
> object
>     to the right of that of your left eye. Your brain makes a 3D image off
these
>     slightly different pictures.
>     Exaggerated this is what you do:
>
>     Left                                 |
Right
>     Object                            |
Object
>                         Position       |            Position
>                         Left eye       |            Right eye
>
>     If the left and right object are placed in the same orientation (not
rotated
> to
>     each other), then your left eye sees the right side of the object a
bit and
> your
>     right eye sees the left side of the object a bit.
>     This is just the wrong way around. Your right eye should see a bit of
the
> right
>     side of the object and your left eye a bit from the left side.
>
> 2. Crossing eye method.
>     By crossing your eyes you look before the picture and your left eye
now
>     looks at the right object and your right eye looks at the left object.
>     Exaggerated this is what you do:
>         Left                               |
Right
>     Object                               |
Object
>                         Position          |         Position
>                         Right eye        |         Left eye
>
>     This is precisely what a 3D picture should be.
>     Now you can understand that the "magic eye pictures" were flipped
>     forward - backwards. Your eyes saw the wrong side of the object.

I'm no expert by any means, but the "random dot sterograms" you see feature
repeating sections of random dots. If you cross your eyes so that the
repertitions line up on top of each other, your brain interprets the repeat
length as 3D depth. Amazingly, you can do this with text too:

00300000300000300000300000300000300000300000300000300
12345612345612345612345612345612345612345612345612345
12345612345612345612345612345612345612345612345612345
12345612346123461234561234512345123456123456123456123
12345612346123456134561234512345612456123456123456123
12345612346123461234561234512345123456123456123456123
12345612346123456123456123461234562345612345612345612
12345612346123456123456123461234561345612345612345612
12345612346123456123456123461234561345612345612345612
12345612345612345612345612345612345612345612345612345
12345612345612345612345612345612345612345612345612345
00300000300000300000300000300000300000300000300000300

Be careful not to "over converge", but you should be able to make out the
letters "PR". (It helps if you view it with a fixed-width font!) By skipping
or adding dots (or in this case digits) you can change the 3D depth. Anyway,
my images use normal effects of perspective to change the rate at which the
pattern repeats, that's all. (Getting a high-contrast random-ish texture
makes it work best.)

Of course, you can "cross" your eyes in two directions - you can make them
more parrallel then they should be by rotating them away from each other (as
if looking "behind" the image), or make them too diagonal by rotating them
towards each other (as if looking "in front of" the image). I myself am
quite good at doing the latter, but not so good at doing the former. If I
could do the former, the first uncorrected image I did would presumable look
correct.

> > PS. Can anyone here see sterograms btw? Kinda pointless if you can't :P
>
> I've made even videos for the crossing eye method and can now look at
> them for hours without effort. Indoctrination of the brain works!!

Mmm... I'm thinking animation 8-) Of course, question is, can you get your
eyes to converge right before the animation is over? lol

> Greetings,
>
> Jaap Frank
>
> PS: I've attached an example. This is a part of a hemoglobine protein
chain.
>       Happy crossing your eyes.

Oooo dear me... I have to shrink the image down several times before I can
cross my eyes far enough... hehehe

Thanks.
Andrew.


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From: Rune
Subject: Re: Sterograms of a cube!
Date: 5 Jan 2003 06:52:15
Message: <3e181c6f$1@news.povray.org>
Jaap Frank wrote:
> The strain for your eyes is the wrong focusing and
> your brain must be learned to do this.

Or rather, your brain must unlearn what it has learned about the
relation between the angles of the eyes, and the correct focusing.
Normally, there is a constant relation between these, where a certain
distance to an object (which means a certain angle between the eyes)
corresponds to a certain focus depth. This is very much a reflex we
have, and thus it is difficult to make our brain use a different focus
for a certain depth, than the brain is used to.

The danger of training the brain to be able to focus incorrectly is that
the natural reflex is weakened. With the ability to focus incorrectly,
as it is needed to see stereograms, also comes the ability to focus
incorrectly in general (or unfocusing, rather). Some years back I was
very much into stereograms and learned to focus incorrectly with ease,
but ever since, I have suffered from the unfortunate side-effect, that
when I have to concentrate on something, but am a bit tired, my eyes
every so often go out of focus involuntarily, and also don't focus at
the same point. Not a huge problem of course, but still pretty annoying.

Rune
--
3D images and anims, include files, tutorials and more:
rune|vision:  http://runevision.com (updated Oct 19)
POV-Ray Ring: http://webring.povray.co.uk


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From: Jaime Vives Piqueres
Subject: Re: Sterograms of a cube!
Date: 5 Jan 2003 07:20:06
Message: <20030105132005.45a3b8d0.jaimevives@ignorancia.org>
Rune wrote:
> [...] but ever since, I have suffered from the unfortunate
> side-effect, that when I have to concentrate on something, but am a
> bit tired, my eyes every so often go out of focus involuntarily, and
> also don't focus at the same point. Not a huge problem of course, but
> still pretty annoying.

 :) I've suffered from this as old as I can remember... much before
seing my first stereogram. This must explain why I can see so easy any
stereogram (I can even browse a stereograms book without the needed to
refocus on each page!)

-- 
Jaime Vives Piqueres
		
La Persistencia de la Ignorancia
http://www.ignorancia.org


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