Virtual Reality: Everything you need to Know

 "Virtual reality is the hot new thing in tech at the moment. Google and a bunch of other companies have put a lot of time (and money) into the development of VR technology with the likes of Google Daydream and the Samsung Gear VR. But how does it work and how will it be implemented with Android? Let’s find out." 

What is Virtual Reality?

Virtual Reality is all about creating a perception in human brain to believe a virtual world as a real one. Virtual reality allows users to immerse in a virtual world unlike screens in-front of them which simply can not produce such effect. It adds 4-5 senses including vision, hearing, touch and even smell. "Seeing is believing" this is what virtual reality does, it makes your brain to believe that you are living a real 3D world. We know the world through our senses and perception systems. In school we all learned that we have five senses: taste, touch, smell, sight and hearing. These are however only our most obvious sense organs. The truth is that humans have many more senses than this, such as a sense of balance for example. These other sensory inputs, plus some special processing of sensory information by our brains ensures that we have a rich flow of information from the environment to our minds. Everything that we know about our reality comes by way of our senses. In other words, our entire experience of reality is simply a combination of sensory information and our brains sense-making mechanisms for that information.

If we somehow provide all these information artificially to our brain, It can be fooled to believe that its living in a real 3D world which we created virtually. And this is what happens in virtual reality.

How Virtual Reality is able to do so ?

Multiple factors allow a VR to do so, First and foremost one is something what we call as stereoscopic display. "A Display that is capable of conveying depth perception is called as stereoscopic display" is what Wikipedia says. We humans can see the world through spectroscopic vision, this means we see the world through our two eyes, at different angles later processed by our brain to get the idea of depth exactly this is what a VR headset imitates. It provides us two displays which display same content at two different angles and our brain artificially is made to believe that it is watching content in real. This is what which can not be created by a screen in-front of us.

Notice how same object is displayed at different angle

Field of view further adds in VR experience, humans have about a 180 degree FOV while looking straight ahead, and 270 degrees with eye movement. The human eye is very good at noticing vision imperfections, with tunnel vision being an example of such a phenomena. Even if a VR headset had a 180 degree FOV, you may still be able to tell a difference. The Vive and Rift both have 110 degree FOVs, Cardboard has 90, the GearVR has 96 and it is rumored that Daydream may have as much as 120. This should, generally speaking, greatly affect the VR experience and could make or break a certain headset for people, not to mention any health issues that we will get into later.

Another Factor which helps in even enhancing this experience is Parallax Effect. In simple words this is what makes objects at far distance look moving slow to us. Also shading and other depth creating effect produce life like visual difference.

  

How FPS and Refresh Rate affects VR Experience ?  

Frames Per Second or FPS means "Number of frames GPU outputs in a single second" and Refresh rate of a display means "Number of frames it can display per second". For Example if A GPU is processing and outputting 60 frames per second then the display integrated with it needs to display 60 frames per second i.e 60Hz monitor will suffice the need. Consider a scenario when GPU is producing 120 fps and we just have a 60hz display connected to it then frames will be wasted and it will produce a Latency Defect which would be make it or break it for a VR Experience. So Calibration of FPS and Refresh Rate is must in a VR. 

Interaction With Virtual reality

This is arguably one of the most important parts of virtual reality. It is one thing to just look around a 3D space, but to be able to move around it and touch and interact with objects is a completely different ballgame. On Android, your phone’s accelerometer, gyroscope, and magnetometer are used to achieve movement of the headset. The accelerometer is used to detect three-dimensional movement with the gyroscope being used to detect angular movement followed by the magnetometer for position relative to the Earth.

Using these sensors, your phone can accurately predict where you are looking at any given time while using VR. With the announcement Google Daydream, Android VR users will be able to use a separate phone as a controller to move and interact within the environment. Desktop VR like the HTC Vive or Oculus Rift either use a controller or controllers reminiscent to the Wiimote for different purposes. Using computer vision, VR accuracy can be greatly improved by having cameras and other sensors set up in the room you are using the VR headset.

VR headsets can have special controllers, as mentioned earlier, but how exactly do they work? Looking at the HTC Vive, there are two infrared sensors and two controllers in the box, totaling 70 different sensors with the headset. All of this tracks you and your controllers allowing you to freely move around the room while playing games. Notice how the Vive controllers have a circle cutout? That is more than likely there for tracking purposes. The Oculus Rift offers a different experience using close to the same technology.

Out of the box, the Rift actually uses an Xbox One controller. But there is an optional set of controllers that offer similar functionality to the Vive, known as “Touch by Oculus.” These two controllers rearrange the One controller’s buttons onto what can only be described as foregrips with large rings covering your fingers. Oculus is keeping the way these work under tight wraps, but the package does include two sensors similar to the Vive so presumably they work in a similar fashion, they may also have accelerometers and gyroscopes as well.

Cyber-sickness

Not meeting an acceptable frame rate, FOV or latency can cause motion sickness. This happens enough to actually coin its own name, known as “cybersickness”. All three of these concepts need to be met to cut down on the changes of cybersickness. Without the correct frames per second with the refresh rate of the display, frame skipping, micro stutters and lag are possible. Latency may even be a bigger problem, with movement and interaction lag caused by slow response times of the hardware, it is possible to completely lose your sense of direction and become disoriented. the experience and may cause some disorientation.  

"Virtual reality is the creation of a virtual environment presented to our senses in such a way that we experience it as if we were really there. It uses a host of technologies to achieve this goal and is a technically complex feat that has to account for our perception and cognition. It has both entertainment and serious uses. The technology is becoming cheaper and more widespread. We can expect to see many more innovative uses for the technology in the future and perhaps a fundamental way in which we communicate and work thanks to the possibilities of virtual reality."

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