created by Becca Creedon
Stereograms
Taking the magic out of "Magic Eye"
What Is A Stereogram
A stereogram is an optical illusion of a two dimensional image made to look 3
dimensional using repetition and spacing to trick the mind.
History
In 1838 Charles Wheatstone discovered the stereogram. He was a British scientist and
inventor. He found an explanation for the way both eyes are used in synchronization to see
one image. Which eventually led him to invent a stereoscope which helped see these
images. By using a series of prisms and mirrors, he was able to combine two images to
make a single image appear 3-D. In 1979, Christopher Tyler created the first
Auto stereogram. And in the 1990's "Magic Eye" became a very popular book containing
several auto stereograms that are still loved today.
How To See Stereograms
Seeing stereograms is an acquired skill. Don't worry if you can't see them at first, it
takes time and a lot of practice to make them work right. But here are a few tricks to get
you started.
-
Pull Background
-
Put your nose close to the image, stare beyond the image, then with out changing
your focus slowly pull back
-
Reflection
- Use a Glass or transparency and place in front of image look at your nose and
wait until the image come in focus (Good for beginners not good for detailed 3-D)
you slowly bring it closer to you. You will see the image out of focus but some
where in between is the 3-D image.
-
See Through
- Copy the image on a transparency, look through to some thing twice as far away
(wall, hand, etc.).
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Almost See It, But Still Not Quite Right.
- Look at your nose then back at the image. It should help the image come in better
focus.
More Help
How It Works
When you look at the stereogram at first glance you see random dots or a random
choppy picture. But when you look closer there are a definite repeated shapes. When the
eyes are crossed just right the repeated chopped up shapes are put together to see the
image. It's like taking two transparencies of the same image then sliding them left or right
until the two "puzzle pieces" fit together. The depth is caused by the spacing of the
chopped images. The constant even repeated image appears flat and at the lowest part
of the 3-D image. The abnormalities in the repetition is what causes the appearance of
depth. The closer apart the chopped shapes are the lower they are in the 3-D image. The
further they are, the higher up they appear.
Types
created by Becca Creedon
Stereoscopic Image
A stereoscopic image is two pictures side by side on is slight lightly different. When the
eyes are crossed the images merge to see a third picture and it appears 3-dimensional. If
the images are big they need the use of a stereoscope. A stereoscope is a device that
uses prisms and mirrors to combine the images.
With the help of a digital camera, take a picture of an object then move an inch or two
to the side and take another picture. Crop the picture until it is small enough to combine
by crossing your eyes. If the images are too wide the effect it harder to see. Then place
the two pictures side by side.
When the picture is taken a few inches away a new perspective is given to the object.
More angles to the object. When that image is combined with the 1st picture there results
in an object with more then one side giving it the popping out effect. It's like a square but
when you add more squares next to it, it becomes a cube.
created by Becca Creedon
Anaglyph Images
These are pictures that have a red/green or magenta/cyan shift. These images are
seen mostly in “3-D Movies”. “3-d Glasses”, a red plastic sheet for the left eye and blue
for the right, are needed to see the image. These pictures are pretty popular when
looking at pictures from Mars. The 3-D images help to feel like you are there. The land
rover has two cameras on the sides, one for red and one for blue which creates and
sends the pictures back to earth for viewing.
Similar to Stereoscopic Imaging, you need a digital camera to take two pictures a few
inches apart. Send the image through Adobe Photo shop and make the one picture that
was taken on the left loose its blue and green color through “Levels”. Put the opaque
image of that on top of the other picture that lost it's red. When looking at the picture the
red shift should be left of the blue.
Anaglyphs use filters to make the brain see the 3 dimensional picture. For more details
on how to make your own anaglyph image visit here. The eye covered by the red filter
sees the red parts of the image as white and the blue parts as black and vise versa with
the blue filter. And the true black and white are perceived as they are. The brain
combines the two images and interprets them as being at different distances and adapts
for color.
Created by Becca Creedon
Random Dot Stereogram
In a Random Dot Stereogram, the picture appears to have dots of white/black and/or
color. The 3-D image is broken up and hidden in the dots.
To make RDS, there are two methods. Using a computer, make a picture of random
dots, like using the spray can tool. Copy and paste the image side by side then on one
side grab a section of one image and shift it to one side slightly. The technique is similar
to stereoscopic images. The second method also requires the use of a computer and a
program called Stereomaker 2.1 it can be downloaded for free here. Simply send an
image into the program and it will give it shading then apply a pre-designed random dots
as a top image then combine them. The program does all the work.
As explained above in the how it works section, the image is like a bunch of puzzle
pieces. When your eyes are just right, the pieces come together.
created by Becca Creedon
Auto Stereogram
A repeated picture is altered to make part of the picture come out. It's similar to Single
Image Random Dot stereograms, except the hidden image is part of the picture as
opposed to being a separate picture altogether.
To make an auto stereogram, take a picture with a digital camera and send it to Adobe
Photoshop or some other photo editing program. Use the lasso tool or another grabbing
tool and select a part of the picture and copy it. Then shift it over a tiny bit.
To explain how it works you should visit the how it works section. When you stop
converging your eyes you combine the repeated images and focus on the parts that don't
belong and your eye tricks your brain into see a 3 dimensional image.
Created by Becca Creedon
Single Image Random Dot Stereogram
Single Image Random Dot Stereograms are a collection of a single 2-D picture with a
hidden 3-D image. The random pictures have chopped up alterations in them that when
they eyes are not converged they come together and create the illusion of a 3-D image.
It's Similar to Random Dot Stereograms, except it uses actual pictures instead of dots.
SIRDS can't be created without the help of a computer. The easiest way to create
these pictures is to use Stereomaker 2.1. When you send an image into the program, it
will repeat the picture for you and give your image a gradient and the program calculates
how deep all the part are and spreads them out accordingly.
SIRDS, Autostereograms, and RDS are all similar in how they work. When the eyes are
focused right, the even, equal repeated pattern appears flat and in the back. Whereas
the alterations create the 3-D hidden image.
Created by Becca Creedon
Wall Paper Image
A wallpaper stereograms originated from the typewriter but now its just as easy to use
a computer and Word. The letters or symbols are repeated at various intervals to create
depth. Instead of using a 2-D picture spaces and letters are used.
This is probably the easiest stereogram to make. All you need is something to type
with. Start by making a repeated pattern like type space space, type space space.
Change the pattern after a couple of rows. Use the spaces as a way to create the depth.
Remember that the pattern must be even and equal to get the 3-D effect. After you create
a semi-lengthy pattern test it to see is it worked right and adjust accordingly.
The spaces between the words is what creates the effect. The smaller the spaces are
between the words, the higher up it is. At first glance the picture looks pinched in the
middle but that's where the 3-D appearance comes from.
Answers
SIRDS looks like this:
Autostereogram looks like:
Colored RDS looks like:
Black and white RDS at the top looks like this:
Related Links
www.answers.com/stereograms
www.mathematische-basteleien.de/stereogram.htm
http://en.wikipedia.org/wiki/Autostereogram
http://shanenj.tripod.com/stereo.html
http://www.kondo3d.com/stereo/gallery/eatit.gif
http://victorian.fortunecity.com/muses/375/stereo/stereo6.jpg
http://www.eyetricks.com/3dstereo.htm
If you would like to learn more in depth about this subject, I would recomend learning
how to make your own. It teaches you a lot about how it works and it's lots of fun.
***Images that were made by Becca Creedon were made with the help of Stereo Maker 2.1 and Adobe
Photoshop/Illustrator
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