3. 3D Applications
Anaglyphs
Almost everyone has already seen anaglyphs; maybe in a strip album, or in a Disneyworld movie where hideous monsters seem to come out of the screen. Do you remember the glasses you had to wear, with one glass in red and the other in green?
Well, these coloured glasses are not designed to make you look silly, but most certainly have some use. Let's explore what happens.
A little refreshment
Do you remember the different elements that are needed to perceive 3D? You can always consult the chapter on stereovision.
An anaglyph consists of two images of the same scenery, each taken from a slightly different angle. Each image is displayed in a colour (which is added in a Geographical Information System): red and green. These two images are superimposed.
Viewing anaglyphs through the red and green coloured glasses produces the following effect:
- The eye covered by the red filter of the glasses perceives the red parts of the anaglyph; the green parts are neutralized to black. (How is this possible?)
- The eye covered by the green (blue/cyan) filter perceives the opposite effect.
As a result, each eye sees only the perspective it is supposed to see. The brain blends together both images and interprets them into a real 3D-image.
Question: Why can't you see the boats in 3D?
