Perspective Projection - Transformations and Projections in Computer Graphics - page 137

Figure 3.57: Example of an SIRDS Dot Stereogram.
are no longer focused on any point, start moving the picture away from you slowly. When
you reach your normal reading distance, you should perceive the three-dimensional
image. It's important not to focus on the image.
The reflection method works for stereograms that are printed on reflecting paper.
Turn and tilt the paper until it reflects light into your eyes. Focus on the reflection and
wait. After a few seconds, you should see the three-dimensional image.
3.14 Autostereoscopic Displays
The autostereoscopic display presents a completely different approach to the problem
of creating and viewing three-dimensional images. Such a display generates a three-
dimensional image without the need for special glasses, any headgear, or any other
auxiliary device. The price for this is a limited field of view. A correct, lifelike three-
dimensional image can be seen only from certain points. A viewer positioned elsewhere
sees either a confusing image or nothing at all.
The original idea of the autostereoscopic display is due to Adrian Travis [Travis 90]
who patented it in 1992 [Travis 92]. Practical autostereoscopic displays are currently
being developed by DeepLight, Inc., of Westlake Village, California [deeplight 06].
Imagine two cameras L and R separated by the correct distance for stereoscopic
viewing (about 6-7 cm), sending images to a computer (Figure 3.58a). The computer
displays the two images alternately at high speed (we say that the images are time
multiplexed). It sends image L , followed by image R , followed again by image L ,andso
on, to a monitor screen. A person is sitting in front of the screen, watching the images.
The two time-multiplexed images are synchronized with a fast shutter device such that