Virtual reality

Virtual reality (VR) is the experience of being in an environment generated by a computer, such that there is little to inform the user that he is in a computer-generated environment instead of a real-world one. It involves technology that uses computer-generated environments to simulate a physical presence in a virtual world. It can be done by using a VR headset. The system uses position-tracking and responds to the user’s inputs.

Virtual reality is related to augmented reality and mixed reality.

The main limitations of virtual reality technology is that the motion tracking is inaccurate. It goes through a filtering process which removes the transients. This gives a floating dizzying effect. This is visible in 2D movies made of VR experiences. This is present in IMU+optical tracking systems including the Oculus Rift CV1, the HTC Vive, the Valve Index, and the Quest 2.

For facial interface headsets like the Rift CV1 and the HTC Vive, the motion tracking issue is further compounded by the mass imbalance of the headset, where it is heaver at the front, making the user's head movements unusual. This is the case for halo headband style headsets too.

Virtual reality is incomplete because it does not cover the full human perceptual space.

Hardware technologies

Head-mounted display

VR is enabled by head-mounted displays (HMDs) such as the Oculus Rift. HMDs utilize stereoscopic displays and specialized lenses along with motion tracking hardware to give the illusion that the user is physically inside the virtual world.

The headset tracks the movement of your head and changes the images shown on the display according to the movement. This process creates the sensation that users are located within the virtual environment. Users of these gadgets are able to interact with the virtual environments. Various input methods, from the traditional game controllers and keyboards to the futuristic hand gestures and voice commands, are available or under development.

Position and rotation tracking

There are 2 classifications of tracking: rotational tracking and positional.

Rotational tracking tracks the 3 rotational movements: pitch, yaw, and roll. It is performed by IMUs such as accelerometers, gyroscopes and magnetometers.

Positional tracking tracks the 3 translational movements: forward/back, up/down and left/right.

Motion tracking can also be used to track your hands and rest of your body through various control peripherals.

Theory

VR is possible using electronics and computer technology. More primitive ideas can be implemented using more primitive technology, such as a fixed stereoscope, or panoramic murals (or 360-degree murals). These fill the viewer’s field of vision with the intention of making them feel a sense of presence at a certain historical event or scene.

Stereoscopes work because the brain processes different two-dimensional images for each eye into a single three dimensional-ish object. A stereoscope gives some sense of depth and immersion.

It could be argued that since the creation of stereoscopic images, people have been interested in making images more three dimensional to enrich its experience.

History

Philco headsight

The Philco headsight used a camera feed and a motion tracker.

Motion tracked-HMDs can be used for immersive remote viewing of dangerous situations, for use in military. An immersive gadget like this does not need to have a computer rendering system attached. It can be attached to a motion tracked camera using an electromagnetic tracking system. This type of gadget can use a video screen for each eye. In this type of system, the head movements of the user are replicated by a remote camera, allowing him to look around the environment.

Ivan Sutherland

Ivan Sutherland developed the first headset with graphics that came from a computer.

Ivan Sutherland developed the concept of the “Ultimate Display”. This gadget could simulate the natural world so realistically that a user could not tell the difference between actual reality and virtual reality. The concept comprised of a virtual world viewed through an HMD and had augmented 3D sound and tactile feedback; computer hardware that created the virtual environment and maintained it in real time; and interactivity between users and objects from the VR world in a realistic way. Sutherland suggested that the gadget would serve as a “windows into a virtual world”, and his idea would become a core blueprint for the concepts that encompassed VR as of 2015.

Ivan Sutherland and Bob Sproull created the Sword of Damocles, an HMD that was held by a mechanical arm mounted on a ceiling. The gadget was connected to a computer and displayed simple wireframe graphics to the user. The arm tracked the user’s head movements but was difficult to use. The contraption was also too heavy and bulky for comfortable use.

Using personal computers and electromagnetic tracking

The Sayre glove was the first wired glove. It was invented by Daniel J. Sandin and Thomas Defanti from an idea by Richard Sayre. Both scientists were from the Electronic Visualization Laboratory at the University of Illinois, Chicago. The glove used light emitters and photocells in the fingers. When flexed, the quantity of light reaching the photocell changed, translating the finger movements into electrical signals.

The VIEW project at NASA’s Ames Research Center was founded with the purpose of producing a VR system that allowed astronauts to control robots outside a space station. The HMD that was developed had super-wide optics (almost an 180-degree field of view).

NASA worked with Eric Howlett at LEEP to develop the optics. LEEP developed the Cyberface. LEEP optics were used by VPL for the first EyePhone.

Smartphone LCD-based VR

The interest in VR regained momentum after Palmer Luckey created the first prototype of the Oculus Rift and launched a kickstarter campaign for its development. The campaign was successful, raising $2.5 million. Facebook bought Oculus VR for 2 billion dollars. After this, virtual reality's popularity hugely increased. Multiple companies invested in the development of their own VR systems. The rise of smartphones with high-density displays and 3D capabilities has also enabled the development of lightweight and practical VR gadgets.

Google Cardboard happened.

SteamVR happened. Then the Oculus Quest VR headsets.