Stereovision is actually the normal way
almost everyone sees in the real world. We all have two eyes and perceive depth by a
mental interpretation of the world we view through those two eyes. Each eye gives a
slightly different perspective on the objects viewed and this slight difference provides
depth cues to our brain. Objects which are relatively close will shift a larger distance
horizontally when viewed from one eye and then switching eyes. Objects which are
relatively far away shift a smaller amount. It is only when we talk about viewing virtual
worlds that things get complicated. Viewing a virtual world on a monitor gives no actual
stereovision depth cues as all objects are rendered at the surface of the monitor. This
does not mean that there are no depth cues at all. The human brain has certain
"experience" which is used to interpret even non-stereovision images. When the
viewpoint into a virtual world is moved objects in the world have a perception of depth
based on viewing them from a different position. This is the same effect as stereovision
except it is linear with respect to time and requires movement to generate the depth cues.
Stereovision produces these depth cues without the need for movement but is enhanced when
movement occurs. Thus, stereovision as it pertains to viewing a virtual world means that
you have the capability to produce two separate images and that each eye sees only one of
the two images. If this is done correctly, your mind will combine the two images in such a
way that you actually have the perception of being "in" the virtual world rather
than just viewing a picture of the virtual world. This adds a level of realism and
immersion to games that is otherwise unattainable. In addition to perceiving depth
"into" the monitor it is also possible to make objects appear to come "out
of" the monitor.
What is required and how does it work?
You must have the ability to present two
independent images of the virtual world, one from each eyes viewpoint. Also required
is the ability to present one image to one eye while preventing that image to be visible
to the other eye and the swapping eyes for the other image. The usual method is LCD
shutter glasses with alternating images on a regular monitor. There are many other
methods, but suffice it to say that with current technology, this is the most cost
effective method and the predominate method used for consumer applications (i.e. games).
As some of you may know the information
normally put on a monitor is being refreshed (written over and over again) at a very high
rate (usually 60 times per second or more) This happens so fast that it looks solid. If
you change the rate to something slower some people will notice flicker in the image.
Televisions display information at a rate of 30 times per second or 30 frames per second.
They use a trick however, which helps to minimize flickering. They interlace each frame.
This means that for one image they show it only on the even scan lines and the next image
they show it only on the odd scan lines. Your mind blends these together and the image
does not flicker (much) even though displaying at a much lower rate.
This information is important when
considering implementation of stereovision. With stereovision one can alternate between
two full images at a very fast rate or one can send two images in interlaced mode where
the even lines represent the left view and the odd lines represent the right view. Each
approach has advantages and disadvantages, but overall the latter is preferred.
In addition to presenting the left and right
image there must be a way to selectively present the correct image to the correct eye.
This is where the shutter glasses come in. The LCD shutter glasses are triggered at the
same time a particular image is displayed so that one eye is blocked from seeing the image
and the other eye is not blocked. By applying an electric signal to one of the LCDs it can
be turned black which is like putting your hand over one eye. Then the other image is
displayed and the signal is changed to change which eye is blocked. This all happens at
such a rapid rate that the human visual system cannot perceive it. What you are left with
is the perception that you are seeing two different images one from each eye, thus
Historical perspective on stereovision
Previous implementations of stereovision had
certain problems and limitations, all of which detract from the appeal of this technology.
The glasses themselves were fairly low quality producing ghosting effects (this is when
the blocking of the eye is not complete and you do see a little of the wrong image). They
all tend to be geeky looking in an attempt to make them appear to be full head mounted
displays, which they are not. Other limitations like only supporting low resolution and/or
low refresh rate also detracted from the value. It is also possible to create a bad
implementation of stereovision in software. Any one of these alone and especially in
combination can produce eye strain, headaches or at best a disappointing stereovision
experience. Lastly, very few games supported stereovision and usually not the most popular
Why SV will be more widely accepted now?
Metabyte has done extensive research and
development to provide the best stereovision solution in the world at the consumer level.
We have combined the best LCD shutter glasses and the best 3D graphics board and the best
driver level software to produce stunning 3D stereovision for a broad cross section of the
most popular games on the market.
The Metabyte approach
Since there is a trend toward designing games
as true 3D virtual worlds there is a fairly short step to making these games stereovision
capable if attacked from the driver level. This short step is not necessarily an easy one
but Metabyte has been in the driver business for years. By leveraging this experience we
have been able to produce stereovision at a low level and transparent to the game. (One
caveat is that the game must be doing the 3D math correctly.) This means that the
development time needed to support stereovision for a particular game is zero!
It also means that there is broad support of
games based on the APIs we support. Currently, support is available for OpenGL with
DirectX coming soon followed by other possible APIs.
When combined with Metabytes
Re2Flex technology on the Wicked 3D board we can do 1024x672 resolution stereovision at a
whopping 79Hz (per eye, 158Hz total) on a single board!
With 2 boards in SLI configuration we can do
1024x1024 resolution stereovision at 68Hz (per eye, 138Hz total). This is the best
stereovision available anywhere in the world at the consumer market level.
Metabyte has also applied its
considerable 3D experience to make needed corrections to the images being displayed. In
general, there are distortions introduced when viewing stereovision on display monitors
that have been corrected. On a more specific note, the crosshair used in Quake type games
is not a 3D object and as such is completely incorrect for stereovision. This has also
been corrected. In fact we have implemented a laser sight type crosshair which works very
well for targeting objects. Add to these items "in game" configuration, a
separate configuration and setup utility, and built on top of the best game board
available and you have a product that takes you to a new level of game immersion.
It is an inevitable fact that the world is 3D
and most people have two eyes. More games are trending towards display from a 3D
perspective. Metabyte's stereovision provides for a more "real world" and
immersive experience! Because Metabyte's stereovision is at the driver level, new
titles are supported more readily and with a higher resolution/refresh rate with the
inclusion of Re2Flex.