How does a virtual reality headset work?June 15, 2018
Virtual Reality devices make you believe you are soaring in a spaceship while sitting in the confines of your home or taking part in a jungle war game while sipping soda in your living room. How is it possible for a device to give you such a realistic experience by simply wearing a headset? In this article, we will try to explain the inner workings of a virtual reality headset.
Although most VR headsets look alike, their inner working is different. For example, the source of imaging:
Heavy duty VR headsets like HTC Vive and Oculus Rift need a PC to run the program that provides an input for the headset. In contrast, the headsets provided by Google and Samsung can be powered by a simple smartphone. These devices will use the smartphone screen and use lenses within the headset to render three-dimensional images. Apart from these two variants, Sony has come up with a console powered VR set called the Playstation VR.
Recently Oculus released a new unit called Oculus Go which works as a standalone device and needs neither a smartphone or a PC/console support. In the coming days, we expect to see more such devices in the market.
All of these headsets create an immersive 3D imagery. It blocks the external light completely and creates a boundary-less virtual environment. Some devices have head tracking and motion sensors to detect every move and provide the respective point of view. So the perspective will be as if you are a part of the scene and you are seeing everything with your own eyes.
The PC based devices will have an HDMI cable that feeds the VR headset and the screens inside the headset are angled to give a three-dimensional view. Sometimes, they may also contain lenses to provide the right amount of depth to the imagery. In mobile based device a simple lens arrangement will be used, along with the phone’s screen to show 3D images. Most headsets have a way to change the lens angle so that you can adjust it to fit your vision.
One of the biggest differentiators between a good VR headset and a bad one is the field of view it offers. A good headset can give up to 110 degree field of view. This will cover your entire viewing angle including your peripheral vision and thus trick your brain into believing it is real.
A good headset will also need to have at least 60 frames per second speed to be believable; else you will feel sick and cannot use the headset for long. The latest Oculus and HTC set can provide up to 90 fps while the Sony’s offering goes as far as 120 fps.
Good head tracking sensors and low latency are also important to make the view believable. A good device can change the scenery based on your head and arm/body movement within 50 milliseconds. If there is a lag, your brain will see through the trick and it won’t be enjoyable.