Stereograms - AVS Forums

Hadoken

7th November 2002 00:08 UTC

Stereograms
I'm writing a few stereographic APEs and I was wondering how many of you are able to see stereograms.
There will be one main APE for rendering stereograms and a few little APEs to help you create the effect you want.
I'll post more info soon if you're interested ;)

Zevensoft

7th November 2002 07:32 UTC

There should be an option for either wall-eyed or cross-eyed viewing (Not all people can do both). Good luck!

Yathosho

7th November 2002 08:29 UTC

yes i can. i even did a stereogram disk that was sold on 17bit software back in the amiga days =)

Tuggummi

7th November 2002 08:40 UTC

Why not add a link to a test page somewhere on the web, so i can test can i see stereographic pictures, because honestly im not sure what they even are. :(

Hadoken

7th November 2002 09:39 UTC

Originally posted by Zevensoft
There should be an option for either wall-eyed or cross-eyed viewing (Not all people can do both). Good luck!

Actually i'm implementing an option for convergence or divergence. Usually cross-eyed people will like convergence, wall-eyed will like divergence. But you can still watch a "convergence" stereogram with the wall-eyed method (and viceversa), the result being an image going inside the screen instead of coming towards you.

nixa

7th November 2002 17:27 UTC

Sorry but I dont know what you are talking about and couldnt find the word stereogram in the dictionary. Could someone explain what it means or translate it to Croatian?

UnConeD

7th November 2002 17:49 UTC

A stereogram is a special image that looks tricks your brain into thinking it's 3D when you look at it in a certain way. There are several different kinds of stereograms (holograms, red/blue glasses, etc), but I think the point here is 'cross-eyed' pictures.

Instead of looking at a cross-eyed picture in normal way, you have to focus your eyes behind or in front of the image (this is hard to do, but there are a few tricks). The image is made so that when 2 different pieces overlap, you get 3D.

One way of doing this is that you render two 3D images, one for the left-eye and one for the right-eye and put them next to eachother. You then cross your eyes so that you see 3 images, the middle one being 3D:

Normal:
Left eye: _[ L ] [ R ]
Right eye: [ L ] [ R ]

Crosseyed:
Left eye: ______ [ L ] [ R ]
Right eye: [ L ] [ R ] ______

The 'middle' picture will look 3D, because your eyes see different images.

However, most stereograms are not two separate images, but one picture containing an repeating pattern that is shifted slightly left/right to give depth when you cross your eyes.

Here are a few examples of stereograms. Note that the image itself won't change, it'll just get depth. If it doesn't work, try changing your distance to the monitor (closer or further).

http://www.kondo3d.com/stereo/gallery/face-e.html
http://www.kondo3d.com/stereo/gallery/xmas2-e.html

There are also random-dot stereograms which use random dots instead of a pattern, but I find them much harder to focus on. Here's what I do:

1) Sit in front of the image about 40-50cm away
2) Cross my eyes
3) Look for 2 pieces that overlap
4) Focus on that piece
5) Relax my eyes

However, there are two kinds of stereograms: crosseyed and paralleleyed, where you either focus in front of the image or behind the image. If the image was created with a different technique than the one you (can) do, you'll see the depth inverted.

Xion(810)

7th November 2002 21:28 UTC

I like the idea of a Magic Eye Stereogram...How would it be done though?

nixa

7th November 2002 21:39 UTC

Thanx Unconed.I didnt see anything but random shifted paterns dough.

Hadoken

7th November 2002 23:59 UTC

I use the method described by Unconed to watch stereograms, but I've heard that for some people it's easier doing it like this:
put something like a pen or a finger between yourself and the screen, then focus your eyes on the pen/finger. You'll see the pen focused and the drawing on the screen defocused. Now move the pen a little back or forward until you have the feeling that both the pen and the drawing on the screen are focused. Then remove the pen and enjoy:up:

Jaheckelsafar

8th November 2002 09:16 UTC

I pick a recogniable shape that is repeated, then slowly cross my eyes until a third image appears between the original two.

ex

orig:
 firstsecond
      
      after:
 secondthirdfrist

(if that helps at all)

mikm

10th November 2002 02:23 UTC

I don't think that stereograms are the best thing to use with AVS. I have never been able to see stereograms, I can see areas that are raised, but they look like random blobs. I also don't know if the APE would work after applying certain effects to it. A stereogram in AVS would look very good. However, an external app that would make stereograms into BMPs would be very useful because it would not require the APE to run, and the program could be used for other purposes (such as the powerfrac app, I use it to make wallpaper for myself)