Working with 3D
Your eyes are 2 to 3 inches apart. As a result, when you look out at the world your left eye sees a slightly different picture than your right eye. Your brain uses those tiny differences to establish distance and depth.
Clever photographers and movie makers have developed 3D techniques that trick our brains into “seeing” depth where it doesn’t exist by simultaneously delivering one image to our left eye, and another to our right eye.
Most of these techniques involve some type of filtering system that allows a movie screen or computer monitor or television to display two images at the same time. A pair of glasses is often used to make sure each eye sees the intended image.
There are basically two pieces to the puzzle: format and display.
Format refers to the way the image pairs are separated. The images may be placed side-by-side in a single video frame. They can be placed one on top of the other. They can also be weaved together line-by-line or in a checkerboard pattern.
Display refers to the technology used to make sure each eye only sees what it is supposed to see. Some common 3D display techniques include:
n Anaglyph: The left and right images are colorized and laid on top of each other with a slight offset. The viewer wears glasses with colored lenses that filter the images. 3D photos and videos in the anaglyph format can be viewed on any standard monitor or television. You just need a pair of glasses, like those included with some versions of this software.
n Polarized: Variations of this technique are used to create the illusion of 3D in many modern movie theaters. Viewers wear glasses with polarized lenses that block light arriving from certain angles. For the home user, a compatible monitor or television and a special pair of glasses are required.
n Active-shutter: With active-shutter systems a wireless communication link is established between the monitor or television and the glasses. With one popular system, the lenses on the glasses darken and lighten hundreds of times a minute in coordination with the images on the screen.
n Digital Light Processing (DLP): DLP displays use extremely small mirrors embedded inside one or more computer chips to reflect light through a lens and onto a screen. For 3D content, viewers wear glasses that communicate with the display to filter the light reaching each eye.