Hi, welcome to Spinning Up in VR! I am Manorama and this is the first of a 9-part tutorial on Virtual Reality (VR) for beginners.
The most fundamental physical concept on which Virtual Reality depends is Stereo Vision.
Stereo vision is implemented by the two eyes of a human and this is what makes depth perception possible. It’s simple: — —
Two Eyes → Two Views!
Two Views are fused in the Brain to create a depth map → 3D View!
The word “stereo” comes from the Greek word “stereos” which means firm or solid. With stereo vision, you see an object as solid in three spatial dimensions — width, height and depth — or x, y and z. It is the added perception of the depth dimension that makes stereo vision so rich and special.
- Stereo vision probably evolved as a means of survival. With stereo vision, we can see where objects are in relation to our own bodies with much greater precision — especially when those objects are moving toward or away from us in the depth dimension. We can see a little bit around solid objects without moving our heads and we can even perceive and measure “empty” space with our eyes and brains.
Here is a short video demonstration on stereovision:
Before we delve into the latest hype on VR, first, let’s look at the history of VR. You may think that the world became aware of this technology two years ago, but VR has its roots buried way back in time.
The history of Virtual Reality can be divided into two phases:
- Virtual Reality in Analog Era
- Virtual Reality in Digital Era
- VR in the Analog Era
Although it was not before 2016 when VR started getting the limelight, the idea actually dated back to the nineteenth century. Devices like the Stereograph, developed during this period, served as a precursor for the modern day VR.
Stereographs were the origin of Virtual Reality. The shocking power of immersing oneself in another world was all the buzz once before — about 150 years ago.
- The stereograph, otherwise known as the stereogram, stereopticon, or stereo view, was the nineteenth-century predecessor of the Polaroid, with an imaginative flair. Placed on cardboard were two almost identical photographs, side by side, to be viewed with a stereoscope. When viewed through a stereoscope, the photograph appeared three-dimensional, an awe-inspiring illusion for anyone during that time.
The author Oliver Wendell Holmes, who invented an affordable stereo viewer for the American market, wrote in the Atlantic Monthly of June 1859 that “the first effect of looking at a good photograph through the stereoscope is a surprise such as no painting ever produced. The mind feels its way into the very depths of the picture. The scraggy branches of a tree in the foreground run out at us as if they would scratch our eyes out. The elbow of a figure stands forth as to make us almost uncomfortable.”
This picture from the Library of Congress is showing a woman actually looking at a stereograph.
- In case if we have head mount display which has two screens showing two images and whereas before this was done with prints of the photograph. So you would print a photograph and show it on the little device. Now we are using screens. When we’re moving towards the 20th century what we are seeing then is an increasing set of dynamic illusions and this was really inspired by the need to train people and in particular training people like pilots.
The first simulators for training pilots came in the First World War so there was a need to train a lot of people very quickly and this picture shows a very common training system called the Link Trainer from the Second World War.
- The idea here was that it simulates some of the controls of an aeroplane so that you don’t have to have your first flight in a single seat aeroplane. The flight simulators have been a very big part of virtual reality since the Second World War with many companies specializing in flight simulators, for example, Evans & Sutherland.
No history of the analog virtual reality would be complete without mentioning Morton Heilig’s Sensorama simulator.
- In the Sensorama simulator, you see a combination of effects. You see a booth that you sit in and you put your head up against a display and it shows you stereo wide angle films. You also get 3D sound unlike many systems you get audio to hear and you also get wind effects, you get aroma effects and the device actually shakes a little bit and this is really the culmination of the analog technologies that are available to filmmakers and creative individuals.
2. VR in the Digital Era
- The earlier Virtual reality had to get more flexible. Analogue media had limited flexibility and the effects were not very much different from watching a static story.
- It was when we got to the digital era we started to see that we can now consider being virtual reality. The key parts being that the person could move around they could choose their own point of view in the film and they could experience audio from a first-person point of view.
Here is a timeline of the growing digital era of VR:
1968Ivan Sutherland’s Sword of Damocles System was the first digital, virtual reality system.
- It was quite a large contraption. It was a head-mounted display, which would be suspended from the ceiling from a mechanical gantry but it had all of the facilities that we can expect of virtual reality.
- The head-mounted display present tracked what the person was doing with their head. As the person moved around the graphics changed and those graphics were rendered from the first-person point of view. Sutherland’s seminal work was indeed a technological marvel that served as the baseline for future VR systems.
1980 VIEW workstation from NASA was built in the early 80s.
- The picture above is from 1989 and what you can see here is sort of the prototype of what we now consider to be a virtual reality system.
- It doesn’t resemble any large mechanical assembly but what you can see is something that sits on the head. It has a large box at the front with screens and the person can move around freely.
- You can also see that the user is wearing headphones and also that they have gloves on their hands so that this system can track their finger movements it can also track where they’re pointing. So this system was used by NASA for various projects, including training astronauts and then this was sort of the start of the industry in the 1990s.
1990Head tracking devices came into being.
- The motivation was to localize the whole head mounted display with respect to global coordinates with high accuracy. Little portable television screens came into being during the late 1980s and early 1990s. Two of these were assembled together with the tracking devices and a fast computer that ran the tracking algorithms and rendered the right pictures on the screens. Nowadays this is almost similar to the other HMDs like Oculus Rift, HTC Vive, etc.
2000 One of the most salient systems built during this time was called the CAVE.
- The systems became more and more professional. Research labs around the world were investing in equipment that could produce virtual reality but the cost was high.
- CAVE is a recursive acronym. It stands for cave automatic virtual environment and the first one was built by Carolina Cruz-Neira, Daniel Sandin, and Thomas DeFanti at the University of Illinois.
- Unlike a head-mounted display, in the CAVE the images are projected on the walls around you and the computer update the projections according to the inputs from a head tracker.
After this, the technology kept on upgrading then came NVIS, Oculus Rift, HTC Vive, etc of the modern era. We will study each of these in the later sections. So read on.
I hope that anyone who reads the entire series in the given order you will have a clear visualization of VR technology. Please feel free to leave your comments below for feedback. You can find me on Twitter(@mnrmja007), Facebook(@mnrmja007) and Medium(Manorama Jha).