Vizard 7 » Reference » Stereo & Displays » Stereo Basics » Stereo basics
7.7
Stereoscopic displays present separate images to a user's left and right eyes in order to properly re-create the normal visual disparity when viewing a scene with two eyes. The resulting 3D is usually very compelling. It is the sense of 3D you have likely experienced at a 3D Imax or other 3D theaters. Vizard provides numerous methods for rendering in stereo. This tutorial shows how to use several of these methods.
Parallel displays (frame parallel)
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Probably the most famous example of a field-parallel display is the old-fashioned view master. This device is specially designed to present separate slides to the viewer's left and right eyes at the same time (parallel). High-end head mounted displays can be thought of a fancy view masters (others use field-sequential mode described below). This method produces the highest quality stereoscopic rendering.
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Anaglyphic
A common technique when hardware is very limited is to use color filters for isolating the left and right eye images. This is actually a case of field-parallel because you view an image that has both red and blue images superimposed on one another. However, Vizard treats this as a separate case because of the rendering technique involved.
Polarized filters
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This is the technique you most often find at theaters such as 3D Imax. These are glasses with polarizing filters that isolate the inputs to the left and right eyes much like the red/blue filters above but retain all the color integrity of the raw images.
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Interlacing
Interlacing works by sacrificing half the horizontal resolution of your display and then drawing the left and right eye images on the even and odd vertical columns of your display. This technique has been recently popularized by the "autostereo" LCD displays that let you see in 3D without wearing any type of glasses. The major disadvantage of this technique is the loss in horizontal (and stereo) resolution.
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This method renders a single image, either the left or right view, at a time and uses some form of shuttering to let the image be seen by only the left or right eye. This means that never do you see with both eyes at the same time, but because the human visual system has significant delays in processing you don't really notice that you're not seeing with both eyes at the same time (much like the impression you have at the movies when quickly alternative still frames induce in you the sense of motion).
This method is flexible and economical. It is used to display 3D images in screen projected systems such as CAVE's and powerwalls, certain monitors and some low-cost head-mounted displays. It does, however, require that the user wear a shutter device which is typically an LCD-based pair of shutter glasses.
