In contrast to Augmented Reality, Virtual Reality (VR) does not generally show us our current environment, but rather scenes and situations that are totally simulated or transmitted from another place and/or time. The initial uses of VR have primarily focused on gaming and entertainment, but in the longer run I expect that training and education will be even bigger.
One of the primary benefits of VR is that it takes full advantage of our stereoscopic depth vision. Anyone with normal or corrected vision in both eyes is accustomed to living in a 3D world, but until the advent of VR our computer and television screens have mostly been limited to 2D, although in the last few years some movies and televisions have supported 3D viewing with special glasses.
A VR environment, however, allows the user to explore the environment and see any part of it from any angle, whereas movies and TV programs in 3D only show the angle that was recorded and presented. They do not allow exploration.
One of the variables that can be applied to VR is the distance between our eyes. Human eyes are normally about 6 cm (2.4”) apart, which gives us excellent 3D vision out to perhaps 30 m or 100 feet. However, as we widen the distance between the cameras in a VR environment, we can extend great depth perception out to almost any distance.
I learned much more about this principle when I took a university class in photogrammetry, which is the study and application of overlapping aerial photos, viewed through a stereoscope, to see the features on the ground in a very exaggerated 3D. A few years after I took the class, I began taking stereopair photos of scenic views, and mounting them for viewing through a stereoscope, which I purchased for this use.
Of the hundreds of stereopair photos I have taken, a few are spectacular. One in particular was taken from a bluff overlooking the Green River in southern Utah. The two photos were taken across a baseline of about 30 meters, looking toward the river perhaps 400 meters away, and with cliffs and sandstone formations extending several miles. Each tree along the river is easy to distinguish, as are features that can hardly be seen in a simple 2D version of the scene.
Not long after I took these photos, I set up the stereoscope at a friend’s house to show to his mother, who is an artist. His 4-year-old son, Ryan, jumped up to look first. As he was constantly in motion, I figured he might look for a couple of seconds. But as he looked into the stereoscope, his body stopped moving, and he was spellbound. After perhaps 15 seconds, his grandmother asked, “Ryan, shouldn’t you give someone else a turn?”
“Uh-huh,” he replied, but did not move. Finally, after perhaps another 15 seconds or so, he reluctantly pulled away from the stereoscope, and immediately was back in motion as before. But at that moment, seeing the effect that a stereoscopic view had on a hyperactive 4-year-old boy, I understood better the power of the medium. It really makes you feel like you are there.
Suggested application
I would very much like to implement VR by mounting cameras on the wingtips of a model plane. Not the quadcopters that are now so common, but a conventional airplane design, with a camera at each wingtip, so that the perspective of your eyes would be several feet apart. The details of the view of the ground would be so much greater than what we can see through a single camera, as we take advantage of our innate 3D ability.
Based on my experience taking stereopair photos, the best 3D effects are seen when the objects viewed are between 5x and 200x the distance between the cameras. As objects come closer than 5x, it can become difficult to focus, and at more than approximately 200x the effect fades into the distance.