INTRODUCTION

First of all I believe an appropriate definition qualifying the concept "stereoscopy-stereoscopic vision" should spearhead this article. To appreciate the essence of stereoscopy some background understanding is essential. A pre-requisite fundamental understanding of basic technical concepts depicting common methods employed in delivering stereoscopy.

Stereoscopy delineates the concept of observation employing dual simultaneous visual inputs from two different angles of an observed image whose image appears on the retinas of the left and right eye respectively. These two angles of the image migrate via the optic nerves to the brain wherein they are merged and interpolated. The computated result of this interpolation is perceived depth.

In essence from the above definition one can easily deduce that the concept understood as stereoscopic vision is unconsciously employed by virtually every living creature on earth with two eyes. In the absence of conscious thought we judge distance and relative positions within our worldly environment perpetually.

Currently stereoscopic implementation has found a strong following in first person shooting games such as Quake, Half life and Unreal. Many reasons exist as to why these first person shooters have enjoyed precedents in the area of stereoscopy. In the past when specific computer games integrated native stereoscopic support superb stereoscopic effects resulted from dedicated programming efforts. Soon afterwards developers develop drivers that interface directing with the raw code of DirectX, open GL and glide. This new era heralded a new beginning in stereoscopic gaming, no longer were users dependent on native stereoscopic code. However, not all games prove suitable candidates for stereoscopy. Some reasons are: within the 3D environment of a game stereoscopic drivers require certain pre-requisite cooperation in order to deliver satisfactory functionality. Sometimes with in a gaming environment programmers take shortcuts, for example a regular 2D bitmap image is sometimes used to illustrate the horizon in a game scene. The stereoscopic drivers are unable to generate stereoscopic code this particular case. The end result would mistakenly place the horizon in front of the scene. First person shooters are less likely to use 2D bitmaps within the active gaming environment. Of course the odd dialogue box and icon may pop up on occasion however fixed 2D bitmap integration within the active 3D environment are infrequent.

Computer power is a crucial factor in these considerations: it is important to understand in rendering stereoscopic environments two frames instead of one need be generated from the CPU graphics hardware combination. Racing simulations are some of the most hardware demanding applications in existence. Until recently CPU graphics combinations capable of delivering suitable performance (frame rates) in stereoscopic mode with high-speed frame rate requirements were definitely in the minority. Accordingly too little cooperation between manufactures of stereoscopic drivers and game developers resulted in minor obstacles which would otherwise easily be ironed out impeding stereoscopic playability. As explained earlier in the 2D bitmap scenario.


FAMILIAR EXAMPLES OF STEREOSCOPY

Many of us still remember the old "view master" with the many circular picture discs at which accompanied them. If any of you still have an old view master disk try observing the adjacent picture frames and you'll notice that a given scene is rendered twice, however from a slightly different angles.

Remember, some methods used in procuring stereoscopic vision don't serve justice to the science of stereoscopy, in fact they serve only to distract from prevailing potential benefits both in entertainment and professional applications. The old method utilising red and blue glasses (some of you may remember the 3D movies from the Fifties)in my opinion and the opinion of many others still lends itself to much eyestrain and loss of colour integrity. This system is known as the "anaglyph" method. For example the image designated for the left eye passes through the red filter which is rejects (filters out) the image designated for the right eye and conversely the image designated for the right eye passes through the the blue filter which in turn rejects (filters out) the image designated for the left eye. Using this method each eye receives its correct image (as explained earlier each image is rendered at a slightly different angle just as a scene in the real world is envisaged through the left and right eyes respectively). In fairness substantial improvements have been made with this method of stereoscopy.


MODERN STEREOSCOPIC OPTIONS

Shutter-Glasses

For the purpose of stereoscopic rendering in PC gaming one of the most widely used, cost-effective and efficient systems currently available are as follows: In order for a regular PC to deliver separate images for the left eye and right eye respectively each time a frame is rendered to the PC monitor, a pulse known as "a refresh or vertical synchronisation pulse" must be delivered from your VGA card to the PC monitor.

The Shutter-Glasses comprise of two LCD panels. These LCD panels polarize (darken) with an applied voltage. In this case the applied voltage emanates from the "vertical synchronisation pulse" delivered from the VGA card each time a new screen full of information or a frame is to be delivered to be PC monitor for rendering.

This being said the two different angles of a scene to be rendered are done in the following way: The image for the left eye is rendered when a vertical synchronisation pulse is applied to the right LCD panel and the PC monitor simultaneously. This darkens the right LCD panel and prevents the image meant for the left eye from being viewed from the right eye. When the image for the right eye is rendered to be opposite occurs.

The switching between the renderings (left and right) is executed quickly enough to trick the brain into believing that both the left and the right frames are being view simultaneously. Just as in real-life the combined image is interpolated in the brain and the relative depths are perceived accordingly.

NB: previously software drivers were employed to drive the LCD panels of the Shutter-Glasses via serial-parallel ports. This status quo restricted compatibility between games. I designed a prototype hardware accessory device (now known as a VGA pass through controller), in the years that followed my original design through the efforts of many industrious people, the VGA pass through controller has been expanded and improved supporting more modes of operation. The VGA pass through controller is positioned between the VGA card and the PC monitor.