FAQs
Three dimensional pictures
Humans, along with many animals, have the ability to see three-dimensional images through the use of stereoscopic (also referred to as stereoscopic) vision. Stereoscopic vision involves the use of both eyes. Three-dimensional movies and pictures work by supplying each of your eyes with a different image. These two "flat" images can look three-dimensional.
When you focus on an object each eye has a slightly different view of it. Your left eye tends to see a little of the left side of the object, while your right eye sees a little more of the right side. Your brain automatically uses this information, plus the angle your eyes have to turn to focus on the object, to supply you with an estimate of the distance of the object.
The most basic method is to get each of the eyes to focus on different images. The two images are placed side by side. The viewer, by crossing their eyes, can interpose one on top of the other to generate the 3D picture. The advantage of this method is that the image has full colour. The disadvantage is that it takes some practice to get the necessary co ordination to do it unless you have a device called a stereoscope. This is the basis for traditional stereoscopic photography.
In recent times, the use of computers have taken an idea originally proposed in the 1960's and created elaborate stereo pairs and integrated them into a single image. There are many names for these auto stereo pairs, such as Magic Eye and 3D Eye. At the time of writing this technique is currently out of vogue, but achieved large coverage during the early 1990's. Two more traditional methods of seeing in stereo are anaglyph pictures and polarised light.
