In recent years, Virtual Reality (VR) technology has finally reached the masses. 2016 was called “The Year of VR” as several actors released their Head-Mounted Displays (HMDs) on the consumer market. While HTC, Oculus and Playstation delivered high quality HMDs that require external computers to run, the year also opened up for high quality mobile VR. Both Google with their Daydream View and Samsung/Oculus with their GEAR VR have provided an easier step for consumers to enter the world of VR. These mobile VR solutions offer better internal measurement units than the simpler Cardboard devices, and also feature simple controllers for interaction. We now see the market spreading out both in quality and accessibility: in 2018 we have both seen the coming of the HTC Vive Pro, a more expensive high-end HMD with increased resolution, and the Oculus Go, which is a reasonably-priced ($200) stand-alone 3DOF (3 Degrees of Freedom) HMD for the starters.
It is natural to wonder how all of this started. Why did we for instance not see much VR before 2016? When it now seems to be relatively easy for commercial actors to push out HMDs down to $200, why did it not happen sooner? Of course, we have had Oculus’ development kits since 2013 — but even this is very recent. When Google released their Cardboard (a simple HMD made out of cardboard and some lenses), it seemed incredilous that VR could be attainable for the smartphone for only 50 cents. This, however, only points us toward how fascinatingly simple the underlying pinciples of VR technology actually are.
In this entry, we will trace the VR tech we see today back to its roots. We will go back about two hundred years, and work ourselves jumpingly forward to the very recent innovative technologies.
In 1838, Sir Charles Wheatstone developed what would be the first Stereoscope. Even before the camera was invented, people were seeing (drawn) images with 3D effect through stereoscopes. Stereoscopy, that is, perceptory illusion of depth, is achieved by displaying a slightly different segment of an image to each eye. Wheatstone achieved this by separating the two images by a piece of wood, and providing a lens directing the light, between each eye and the corresponding image. While looking through the stereoscope, our brains perceive the two images as one image, with the added 3D effect due to the varying segments of the images. This effect is simply caused by an utilization of how our eyes and brain work, by combining the sensory data from each eye into one. We may, for instance, most likely be able to recall sometimes «seeing double», when our brains have yet not our varying visual impressions.
Since Wheatstone, different stereoscopes have been produced all the way up to the Google Cardboard or other HMDs; which instead of drawn images, or later photographs, utilizes a screen to deliver the imagery to the eyes. Actually, in the early 1900s, Stereoscopes functioned as home entertainment devices, and «stereo cards» such as the image seen below could be purchased from photography companies.
Stereoscopes and modern day Virtual Reality HMDs share the essential feature of stereoscopic depth illusion (3D). Apart from that, however, a lot has obviously happened since 1838, which we now regard as essential for the feeling of presence and realism, and which makes the technology capable of simulating realities. The most important of these have been moving images, 3D environments, interaction, and 360 degrees of orientation. With the stereoscope, images very static in every sense.
In the mid 1950s, however, some people saw the opportunity to spice up their stereoscopes a bit. A bold attempt at enrichening this, was the Sensorama. In addition to providing a stereoscope with motion pictures in 3D and color, all quite revelutionary, the device had fans for simulating wind, odor transmitters for smell of the environment, stereo sound, and even a moving chair!
The idea of the Sensorama, or VR in general, can as many other innovative future-defining ideas, be found in science fiction literature. Before its conception, in the 1930s, the science fiction writer Stanley G. Weinbaum introduced the idea of «Pygmalion’s Spectacles». By wearing these, the user could experience a fictional, or virtual world, with holographs, smell, taste and touch, and make the virtual come alive. Pygmalion, which «Pygmalions Spectacles» were named after, were a Greek sculptor who fell in love with his sculpture, and so begged Venus that it would come alive. The Myth sheds an interesting light on VR as an ultimate dream of humanity, to create realities for ourselves to inhibit, or to create images in the format of reality.
To take a leap towards another paradigm shift in VR tech, we must enter the land of 1s and 0s. The Stereoscope slowly moved from drawn images, to photographs, and further to moving images with the Sensorama. None of these, however, supported spherical environments that could be perceived in all their 360˚. To achieve this, certain sensors and further computation based on their sensory input has been necessary. The most important and interesting of these sensors, has been the Gyroscope.
The Gyroscope was given its name by Phycisist Jean Bernard León Focault in 1852 who used the device as a means to prove the rotation of the Earth. The gyroscope is a device consisting of a spinning top with a pair of gimbals. Its origin can not be traced to a single invention or inventor, as tops have originated in many ancient civilizations — however, unlike the «complete» Gyroscope, these were not necessarily used as instruments. Although Focault’s gyro were not the first that were used as a measuring instrument, its affordances work well to examplify the usefulness of gyroscopes in VR HMDs; the important feature it affords is the measure of rotation, which key lies in the Gyroscope’s tops’ possibility for free rotation.
Gyroscopes are fun artifacts to play with as they seem to defy gravity. While spinning, they can remain stable in most positions. If placed on a platform, that unlike the gyro remain stable, the position in terms of rotation can be measured relatively to the platform, and as such we can also measure the rotation of a HMD. It should be noted, however, that the gyroscopes of today are not pretty mechanical objects of brass anymore, which, although they do no longer satisfy our aesthetic appetite, at least have the benefit of fitting into our smartphones and HMDs. Today, gyroscopes have heights, widths and lengths of only millimeters, which opens the possibility for placing them inside smartphones and HMDs.
The Sword of Damocles
Fifty years ago, in 1968, Ivan Sutherland and his student Bob Sproull created the first computer-driven stereoscopic (3D) Head-Mounted Graphical Display with 360˚ head-tracking. The HMD was not exactly lightweight, and was named after the «Sword of Damocles» because of the heavy stand hovering over its users head. As can be seen in the illustration below, the head-tracking was mechanical, and did not in fact use a Gyroscope. Later, however, this became a more fruitful approach, so as to avoid the massive device rotating over the users head.
The field of view and graphical fidelity of the Sword of Damocles were obviously quite low, yet the Sword of Damocles is the first widely known HMD, and has since its dawn inspired and launched further decades of VR research.
Towards the modern HMD
Since the invention by Sutherland and Sproull, creation and use of HMDs was seen more and more within research. As computational power became faster and cheaper, the HMDs decreased in size, and increased in field of view, graphical fidelity and refresh rates. Yet — even back in the 1990s for instance, the technology was still expensive, and poor in terms of graphical realism. It often caused cybersickness due to low refresh rates, and high motion to photon latency. Of this reason, as with any really powerful computer from that time, VR was reserved for research universities that could invest into the technologies, or businesses with resources to experiment with the technology. There were some attempts at commercializing VR for gaming purposes, such as the SEGA Genesis and Nintendo Virtual Boy — however, both of these remained largely as prototypes and were later discontinued. To this day, none of these companies has since experimented with the technology, although Nintendo in 2010 released the Nintendo 3DS which utilizes a stereoscopic display that does not require any glasses.
Since the Sword of Damocles, VR technology has undergone small incremental changes leading to where we are today, mainly as a result of general computer and graphics research, and the natural progression of Moore’s Law; today our processors are smaller and more powerful, and our screens of higher resolution.
In addition to this, however, there are certain very recent technologies that have impacted the VR as we know it today as well. In Matrise’s glossary, we briefly present and define some of these technologies. Some that can be read about is Foveated Rendering and Low Pixel Persistence Modes.
Did we miss anything? Any thoughts are welcome in the comments section.