How do Virtual Reality Headsets Work?

Imagine exploring the rough terrain of Mars or climbing Mount Everest from your home. Sounds astonishing, doesn’t it? Well, this is what Virtual Reality headsets bring to the table. In this post, we’ll get to know how do Virtual Reality Headsets Work?

Virtual Reality is a fake world which feels almost real. Just like the real world, a person able to look, move around and touch the objects in the virtual world. The only difference is, the virtual world can be edited as compared to the real world.

It is the buzzing “it” technology, and is taking the world by storm. The VR is not only limited to play games on PS4, but it has a wide range of applications, including healthcare, military training, construction, medical, and so on.

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Fairly, it’s an easy-to-use device, by simpling mounting it on your face and wrapping the strap around your head. However, in order to fully understand the working of a VR headset, there are some fancy terminologies set by developers which are good to know. At first glance, these terms might feel daunting, but if you take a deep breath and read this guide thoroughly and patiently, I’m sure you won’t feel lost.

VIRTUAL REALITY HEADSETS

Before explaining how do virtual reality headsets work? We need to know what is a VR headset. Virtual Reality Headset is a head-mounted device which immerses the user into a computer-generated fake or simulated world. VR headset usually works in tandem with a computer or console, or a smartphone.

HTC Vive and Oculus Rift, the two leading VR Headsets, require a computer or a console to be connected to work. On the other hand, Goodge Daydream and Samsung VR need the smartphone to be fitted inside headset in order to function.

Below is a list of terminologies which would help you understand how do virtual reality headsets work? By going through each terminology, you would understand how VR headsets operate.

STEREOPSIS & STEREOSCOPY

The eyes of human and animals are located at different lateral positions on the head, resulting in two different images projected by the retinas of eyes. The difference is observed in the horizontal position of objects in the two images. So, the depth and 3d structure obtained by deriving both images from the eyes is known as stereopsis. And the technique to enhance the illusion of 3d depth images by means of stereopsis is known as Stereoscopy.

The VR headset uses stereoscopy to create the 3d structural environment by feeding the image to both the retinas of eyes. VR headset sends either two separate video signals to one display or uses 2 LCD displays; each for one eye.

LENSES

There are lenses which are placed between the eyes and display. These lenses create a stereoscopic 3D image by angling the two images in a similar fashion as our eyes. Lenses provide a wide field of view and help in focus because the eyes can freely roam inside the headset. If eyes are out of focus inside the headset, then continuously refocusing on screen can cause eye strain.

Most of the manufacturers use Fresnel Lenses. The issue seen with lenses is ridging of the lenses when the headset is not properly worn. Another issue which is induced by lenses is distortion and chromatic aberration.

Finally, corrective eyeglasses can be avoided by adjusting the lens dynamically according to the user’s prescription.

REFRESH RATE

To avoid glitches on the screen, the refresh rate should be a minimum of 60 frames per second. Anything below this would result in feeling sick because of the stuttering in the video. Fortunately, all the VR headsets have a refresh rate higher than this.

The PlayStation 4 – Virtual Reality headset has a whopping 120 frames per second, while the HTC Vive and Oculus Rift have 90 frames per second.

Low refresh rate can cause Judder. Judder is a manifestation of strobing and smearing, meaning the motion becomes blurry and more than one image starts to appearing; which can cause motion sickness.

HEAD TRACKING

Considering Head Tracking, the sensors in the headset track the movement of the head of the user and respond by shifting the picture according to the movement of your head. In this way, the picture follows your head positioning, making the experience a lot more realistic. 6DoF; six degrees of freedom, is the system which is used to plot the head’s position on X, Y, and Z-axis.

There are a few components which are used in the Head Tracking system of the VR Headset, including a gyroscope, accelerometer, and a magnetometer. The PS4 VR headset uses 9 LEDs around the headset to monitor the head position and uses external cameras that control these signals.

LATENCY REQUIREMENT FOR HEAD TRACKING

The VR Headset needs to have a high latency rate. This is because it is extremely important to track the movement of the head with high precision. Failure to do so can result in the flickering of the screen or lag in the video which can cause motion sickness to the user. High latency rate also helps in improving the refresh rate of the headset.

According to a Valve Engineer, ideal latency would be 7-15 milliseconds.

It has been reported that the Oculus Rift has a latency of about 30 milliseconds. And for the user to feel comfortable, the lag should not be greater than milliseconds.

3D AUDIO

To completely submerge in the environment of VR headset, high-quality sound is undeniable. With the help of the headphone, 3D audio is generated which makes it feel like the sound is coming from behind, front or next to them. The sound is in sync with the video and complements the environment. 3D audio creates a realistic soundscape for the user.

MOTION TRACKING

The VR Headsets have wireless controllers which help you in interacting with the objects or items in the virtual world. If you’re playing a game and want to open a chest for loot, then by pressing a button on the controller it renders the chest to open making it feel like you’re controlling it. Along with buttons, there are sensors which detect gestures such as pointing and waving. When you’re playing a first-person shooter, you’re holding a gun and pointing it in a different direction. That motion is usually mapped by the sensor which helps in aiming.

FUTURE OF VR

VR is the future. There is a stream of technologies which will be shaping our future, such as Artificial Intelligence, Smart Grids, IoT, Machine Learning, Cryptocurrency and so on. VR is one of them which will make our future much convenient and reliable.

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