AR (Augmented Reality)
A technology that superimposes a computer-generated image on a user’s view of the real world, providing a composite view. AR can be experienced using a smartphone or tablet screen, or wearable devices such as connected glasses (Google, Microsoft, Magic Leap and Apple are all working on AR headset solutions).
VR (Virtual Reality)
A three-dimensional, usually computer-generated environment which can be explored and sometimes interacted with using a closed headset that provides full immersion into that environment. VR environments are mostly designed for gaming, entertainment and exploratory experiences, but the technology is also used for simulation purposes in various industries (industrial prototyping, military, education, healthcare).
VR Headset (or Head Mounted Display – HMD)
A VR headset consists of a goggle-like device which includes a display and lenses to let you explore virtual reality environments. There are currently two main types of HMDs: tethered and mobile (or portable).
Current high-end tethered headsets designed for gaming (requiring a PC or gaming console capable of delivering a rich graphic experience) include the Oculus Rift, the HTC Vive and the PlayStation VR, all commercially released in 2016.
Mobile headsets, powered by 4-6 inch smartphones, offer a more casual, entry-level experience, with a focus on video and lightweight graphics games. There are literally hundreds of models available on the market, from the under $20 Cardboard viewers to the more sophisticated GearVR by Samsung, and standalone headsets that do not require a smartphone. An good list of mobile HMDs can be found here.
Google Cardboard is a – yes, cardboard – headset that turns Android and iOS phones into VR devices, removing one of VR’s biggest barriers to entry: cost. Since its launch in 2014, Google has sold well over 1 million Cardboard headsets. This low cost viewing solution has sparked a lot of competition from other headset makers, turning the word ‘cardboard’ into a generic term for “entry-level mobile VR headset”. In 2015, the New York Times, partnering with Google, gave away 1.3 million headsets to its subscribers, allowing them to experience custom-made immersive editorial content.
Field of View (FOV)
The field of view, measured in degrees, is the extent of the observable world that is seen at any given moment. In VR, FOV is the extent of your natural vision that is filled by the headset’s display. Humans have a FOV of around 180°, but most HMDs offer between 50 and 110°.
Often labeled as the holy grail of VR, presence is the perception of being physically present in a nonphysical world, or a state of consciousness where the VR user experiences a simulated experience that appears real and thus feels real. Presence can be measured as the degree to which the virtual environment faithfully evokes a sense of reality that causes the user to suspend disbelief. The greater the suspension of disbelief, the greater the degree of presence achieved.
VR (or motion) sickness
Virtual reality sickness occurs when exposure to a virtual environment causes symptoms that are similar to motion sickness symptoms (discomfort, headache, stomach awareness, nausea, vomiting, sweating, fatigue, drowsiness, disorientation, and apathy). VR sickness is primarily caused by the disconnect between what the eyes see and what the vestibular sense feels. There are various technical aspects of virtual reality that can induce sickness, such as mismatched motion, field of view, motion parallax, latency and viewing angle. Also, the amount of time spent in virtual reality increases the presence of symptoms. VR companies are working hard to resolve this issue. As of 2016, most hardware-related factors have been successfully addressed.
Latency is the tiny but perceptible delay between when you move your head in VR and when the image in front of your eyes changes — creating a mismatch between the motion you feel (with your inner ears) and the image you see (with your eyes). In real life, the delay is essentially zero. In VR, a 20 millisecond latency is considered low and acceptable for a comfortable experience.
Haptics (touch feedback)
Haptics recreate the sense of touch by applying forces, vibrations, or motions to the user, through feedback devices (think of vibrating game controllers). In VR, headsets primarily use sight and sound to immerse the user, but haptic gloves and suits are currently in development to offer a fully immersive physical experience of digital worlds.
The 4D moviegoing experience enhances a 3D film screening with physical effects that occur in the theatre in synchronization with the film. Effects simulated in a 4D film may include rain, wind, fog, lightning, vibration and scent. As of 2016, most of the world’s 4D theatres are located in Asia and Latin America.
A 360° video is created with a camera system that simultaneously records all 360 degrees of a scene. Viewers can pan and rotate a 360 video’s perspective to watch it from different angles. 360 videos can be viewed on mobile devices, but a fully immersive viewing requires a headset. Since 2015, both YouTube and Facebook support 360° videos.
Stitching is the process of combining multiple video sources with overlapping fields of view to produce a fully immersive 360° video. Stitching is usually handled by dedicated software that allows to process multiple sources for synchronisation, exposure and white balance, anti-vibration stabilization, and orientation control.