Monday, January 8, 2018

Explained: How does VR actually work?



How does VR work? How does a virtual reality headset make you think that you're sitting in a spaceship in a distant galaxy when you are, in fact, actually about to bump into the kitchen counter? Well, with the army of VR devices expanding, we'll be explaining how they actually work.

While devices generally take the same form, how they project imaging in front of our eyes varies greatly. The likes of the HTC Vive and Oculus Rift provide PC-based operations, though major players such as Google and Samsung offer more affordable, smartphone-based headsets. Sony has also managed to crack the console scene with its Playstation VR.

Standalone VR is something you'll be hearing more of too - in 2018 Oculus will launch the Oculus Go, and Lenovo's standalone Daydream headset is also expected.

Once your headset and power source are secured, some kind of input is also required for you to connect - whether this is through head tracking, controllers, hand tracking, voice, on-device buttons or trackpads.

Total immersion is what everyone making a VR headset, game or app is aiming towards - making the virtual reality experience so real that we forget the computer, headgear and accessories and act exactly as we would in the real world. So how do we get there?

VR headsets like Oculus Rift and PlayStation VR are often referred to as HMDs, which simply means they are head mounted displays. Even with no audio or hand tracking, holding up Google Cardboard to place your smartphone's display in front of your face can be enough to get you half-immersed in a virtual world.

The goal here is to create what appears to be a life size, 3D virtual environment without the boundaries we usually associate with TV or computer screens. So whatever way you look, the screen mounted to your face follows you. This is unlike augmented reality, which overlays graphics onto your view of the real world.

Video is sent from the console or computer to the headset via a HDMI cable in the case of headsets such as HTC's Vive and the Rift. For Google's Daydream headset and the Samsung Gear VR, it's already on the smartphone slotted into the headset.

VR headsets use either two feeds sent to one display or two LCD displays, one per eye. There are also lenses which are placed between your eyes and the pixels, which is why the devices are often called goggles. In some instances, these can be adjusted to match the distance between your eyes, varying from person to person.

These lenses focus and reshape the picture for each eye and create a stereoscopic 3D image by angling the two 2D images to mimic how each of our two eyes views the world ever-so-slightly differently. Try closing one eye then the other to see individual objects dance about from side to side and you get the idea behind this.

One important way VR headsets can increase immersion is to increase the field of view i.e. how wide the picture is. A 360-degree display would be too expensive and unnecessary. Most high-end headsets make do with 100 or 110 degree field of view, which is wide enough to do the trick.

And for the resulting picture to be at all convincing, a minimum frame rate of around 60 frames per second is needed to avoid stuttering or users feeling sick. The current crop of VR headsets go way beyond this - Oculus is capable of 90fps, for instance, while Sony's PlayStation VR manages 120fps.

Also see PLAYSTATION VR CONTROLLER review

No comments:

Post a Comment

Explained: How does VR actually work?

How does VR work? How does a virtual reality headset make you think that you're sitting in a spaceship in a distant galaxy when you ar...