Stereogram – A New Way to Look at the World
Stereograms or 3D images, which represent nothing but an optical illusion, appearing when one follows a particular method of eye focusing at the specifically rendered flat two-dimensional source images, has been a kind of a total world craze in the 1990s. People of all ages spent time gazing at some odd-looking and obscure images, waiting until the eyes catch the appropriate focus and the hidden 3D image of some object or text will be revealed in the three-dimensional form. Introduced and widely popularized under the trademark “Magic Eye”, over 20 million books with stereogram images were sold worldwide, hitting the top of the New York Times Bestseller List.
By the end of this article we will explain the basics of stereogram and give you some tips on mastering the “magic eye” technique, so that you could find out what is hidden behind this bouquet of blue roses and other similar stereograms.
Stereogram – History, Types and Science behind
Sir Charles Wheatstone, a Victorian scientist best known for his contribution to the development of telegraphy, made many amazing discoveries: from English concertina (a musical instrument) to the stereoscope – a binoculars-like device, capable of displaying 3D images.
The idea was based on the concept of the binocular vision in humans, and stereopsis in particular. To put it in simple words, humans use both eyes to perceive visual information, but since our eyes are placed at some distance between them, each eye sees the object from a slightly different angle. Thus, the picture, perceived by the left eye, differs slightly from the one, received by the right eye. Human brain then renders both pictures and generates the three-dimensional image. This is the usual way we see the world surrounding us.
Upon understanding the processes of binocular vision, scientists decided to make a little trick with brain, offering two slightly different flat or 2D images for each eye and letting brain do the job on generating one stereo image. That is how stereoscope was invented. By the way, stereoscopes were so popular, that enterprising citizens of the Albion soon funded the London Stereoscopic Society in 1850 and started the commercial production of the devices. By the end of the 19th century, stereoscope was the must-have accessory for every house, where people did their best to remain in line with the latest fashion trends. Below you can see a couple of examples of stereoscopic images of those times.
After stereoscopic images, another form of stereograms, called anaglyph images, appeared at the middle of the 20th century. Here the illusion of 3D scene was created by using different color filters in the glasses for the left and right eye. Besides, the image itself contained shifted color schemes to create a three-dimensional illusion, like at the example below:
However, the real breakthrough in stereography occurred with the development of computer and computerized methods of video and graphics rendering.
Autostereogram – a New Way to look at the World
Autostereogram differs significantly from earlier forms of stereograms. The key difference here is that it is no longer necessary to use two images and special glasses to generate a 3D image. Autostereogram is a single 2D image, generated by a computer, and one can see the 3D scene on it by converging or diverging the eyes. Single Image Random Dot Stereogram is the most advanced form of such stereograms, where a 3D image is secretly hidden behind some noise-like texture. The first such stereogram, where only one source image was used to see a 3D scene, was created in 1979 by Tyler and Clarke. During the 1990s autostereograms received a new boom in their wide popularization thanks to Magic Eye books with the collection of multiple 3D images. Now, stereogram seems to be passing to the next level of its development with the introduction of 3D computer displays and multiple gaming video hamlets. Modern SIRD stereogram commonly looks like the one below:
Stereogram Viewing Techniques
In order to see 3D images, it is necessary to master certain techniques of looking at the source image. Of course, if you go to the 3D cinema, you will be provided with special glasses, ensuring you to see the correct three-dimensional scenes with no efforts from your side. However, in order to see 3D images right on your computer screen, it is necessary to train your eyes a little.
Hold the picture closely to your face with the nose literally touching it. If you experiment with a computer it is better to move your head to the screen and not vice versa. When the picture is that close, your eyes won’t be able to focus and all you will be able to see will be the blurry image. Do not try to focus on the image, just relax and start moving the picture away from your face slowly. Again, do not let your eyes move or rotate to catch the focus on the picture. At some point, you will see certain visual transformations of the picture and you brains will soon catch the hidden 3D scene. Try to fixate this eye position; after a bit of practicing your eye will remember this position and you will be able seeing 3D pictures on the go even without moving the picture back and forward.
Place the picture 30-50 cm from you face. Imagine you are looking not on the image, but through it at some object located behind the picture. Your eyes will thus be unfocused. Then try moving a picture back and forward. Give your eyes some time and soon the 3D image will appear.
Seeing stereogram can really be tricky at the beginning, but once you get the technique you will be able to see all the magic of stereoscopy without any serious efforts. By the way, some people say that seeing stereograms may be helpful for your eyes, especially, if you spend much time staring at the computer screen.
Stereogram Tools and Gallery
If you are reading this, it means we were successful in drawing your attention to stereography. Now, how about creating some cool stereogram by yourself? To do so, you will not have to learn all the science behind the stereography and 3D images, just search the network for some software applications or online services for creating customized 3D images. To give it a start, you can use one of the following links:
And now let’s move to the most exciting part of the article – to the gallery of stereograms! All of these are SIRD autostereograms, so you can try one of the methods described above to see what exactly is hidden on these fantastic images. Intentionally, we are not giving the descriptions of all images to give you a chance to reveal the secret on your own.