VR Headsets Work through a Combination of Different Tracking Technologies
Virtual reality has made its way into the consumer tech realm. Now, from the comfort of your own home, you can experience other worlds, visit real landmarks in a virtual realm, and play realistic games like you never would've dreamt of as a kid.
All of this capability hinges on some pretty interesting technology hardware – the VR Headset.
VR headsets range from the simplest ones being made out of cardboard and a few lenses all the way up to being sensor filled LCD screen glasses packed with technology. The HTC Vive, Oculus Rift, and Playstation VR are by far the most common PC-based options, and Samsung Gear VR and Google Cardboard both work by utilizing your smartphone. These two different kinds of headsets, PC or phone-based, work in similar ways but have to utilize different sensor capabilities to make each of their functionalities work.
There's another realm of VR headsets too, that's standalone VR. The two primary standalone VR headsets are the Oculus Go and the Daydream headset. Standalone VR, in short, simply means that you can put on the headset and be good to go. You don't need another device like your smartphone or computer to run the show.
Now that we understand the basic VR headset options let's try to understand the technologies these headsets are utilizing.
The basic setup of VR headsets
VR headsets will typically require some kind of input to function, or at least for you to interact other than seeing in the digital world. This ranges from simple head tracking to controllers or even to voice commands and controllers. Different types of headsets will utilize different methods of controls.
Devices like the Oculus Rift and Playstation VR are known as head-mounted displays or HMDs. These devices have no audio recognition or hand tracking capabilities natively built into the headset.
The goal of VR headsets is to generate a lifelike virtual environment in 3D that tricks our brains into blurring the lines between digital and reality. Video for headsets is fed from a source, either through the smartphone screen, through an HDMI cable from a computer, or natively displayed through the headset's screen and processor.
The video or image placed on the VR screens is split in two, with an individual view for each eye to create a 3D perspective. All VR screens will also utilize lenses between the screen and your eyes. This helps distort the screen-presented image into something more lifelike for our eyes.
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In short, the lenses shape the picture from the flat screen into a stereoscopic 3D image. This is done due to the angle and type of lenses in the headset. The lenses distort the two independent images, one for each side, into the correct shape for how our eyes would otherwise see the real world.
The actual images for each eye are displayed slightly off from one another. If you close one eye back and forth in the headset, you can see the objects in VR dance back and forth. It's this principle that lets the VR be 3D.
One of the coolest things about VR isn't just the fact that you can see in 3D though, it's more so the fact that you can look around in 360 degrees and have the image/video respond to the way you move your head. When this happens, it isn't the screen physically moving, rather it's what's being displayed on the screen that's moving (obviously), so it takes a combination of impressive sensors and software design to make this illusion work.
The sensors that make VR headsets work
In VR headsets that have sensors embedded in them for head tracking, something known as six degrees of freedom, or 6DOF, is the concept used to make head tracking work. This system basically plots your head in an XYZ plane, and measures head movements by forward, backward, side to side, and yaw and roll.
The sensors that make the 6DOF work are gyroscopes, accelerometers, and even magnetometers. The Sony Playstation VR headset even uses LEDs placed externally that are tracked with an external camera to develop a highly accurate position of your head in VR.
As headsets are working to be the most realistic they can be to trick our brains into thinking they're in a virtual space, the lag and response rate needs to be flawless. Head tracking movements need to be less than 50 milliseconds. Otherwise, our brains will think something is up, and we might start to get sick. Coupled with this response rate, the screen's refresh rate needs to be high, upwards of 60 to 120 fps. Without high response rates, VR headsets would be nausea-inducing devices.
To complete the sense of realism, most VR environments will utilize Binaural or even 3D audio to create a complete audio-visual landscape of the virtual environment. This is simply done through the wearing of headphones, but the sound itself is then adjusted through software from feedback from the position sensors.
Premium VR headsets have the ability to motion track, whereas the cheaper headsets just have a static or motion-activated viewpoint and require other more manual inputs, like from a gaming controller. Head tracking is one of the key capabilities that make these headsets more premium and thus make using them feel more real.
Oculus now actually offers extra sensors you can purchase for your VR headset that allow players an extra level of accuracy in the VR environment.
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And when it comes to tracking your physical position within a room, Oculus now offers an experience to match the HTC Vive, which it didn't do out the door. Rift owners now have the option to purchase a third sensor for $79 and add more coverage to their VR play area.
Different headset brands will utilize different tracking sensors and arrays, but in general, it involves some form of LED point tracking on the headset that feeds to an external camera.
That camera then processes the movement of the points and interpolates it into the display movement on the camera.
So, VR headsets work through a combination of lenses, offset screens, and motion tracking technology all to create a digital VR environment more believable than ever.