With the development of the internet, it has become increasingly integrated into daily life and entered new fields. This year is widely recognized as the first year of a major explosion in virtual reality, and China's VR industry has also experienced explosive growth. So, what exactly is virtual reality technology?
Virtual Reality (VR) was first proposed by Jaron Lanier in PL (1980). It refers to the use of computers to simulate a three-dimensional virtual world that provides users with visual, auditory, and tactile sensory experiences. Users interact with this virtual world using special input/output devices.
I. Characteristics of VR
Immersion: refers to using computer-generated three-dimensional images to place people in a virtual environment, just like in the real objective world, giving people a sense of being there;
Interactivity: In this computer-generated virtual environment, people can interact using some sensing devices, just like in the real objective world. For example, when a user grabs an object in the virtual environment, their hand feels like it is holding something, and they can feel the weight of the object.
Imaginative: Virtual environments allow users to immerse themselves and acquire new knowledge, enhancing their sensory and rational understanding, thereby deepening their concepts and generating new associations. Therefore, it can be said that virtual reality can inspire people's creative thinking.
II. Working Principle of VR
1. Basic Hardware
Current VR devices can be roughly divided into two categories: one is those that require external hardware to assist in computation, such as Oculus Rift and HTC Vive, which need to be connected to a high-performance computer to operate.
Another category relies on the device's built-in hardware to complete the calculations, such as the PicoNeoVR all-in-one headset and the DPVR all-in-one headset. These VR glasses are characterized by the fact that they do not require the assistance of other devices and can work completely independently.
2. Head tracking
Head tracking means that when you wear a VR headset, the scene in front of you changes as you turn your head up, down, left, and right. A system called 6DoF (six degrees of freedom) converts your head movements into three dimensions: x, y, and z, to accurately measure head movements such as forward, backward, left, and right.
The head tracking system utilizes a range of different internal components, such as gyroscopes, accelerometers, and magnetometers. Sony's PSVR also uses nine LEDs on the headset, supplemented by the camera monitoring on the PS4 to provide 360-degree head tracking. Oculus also has 20 LEDs, but they are not as distinctive as Sony's.
Achieving head tracking technology requires reducing latency—we're talking about 50ms or less, so that we can't perceive the asynchronous nature of the image while moving. The Oculus Rift achieved an impressive 30ms latency. Reducing latency is crucial for any device that tracks motion input.
Finally, headphones can also be used to enhance immersion. Binaural or 3D audio can be used in applications and games, in conjunction with head-tracking technology, to give wearers a truly immersive audio experience.
3. Motion tracking
Compared to Cardboard-like devices, head tracking remains the biggest advantage of advanced headsets that haven't yet been officially released. However, the "big players" in the VR field are still dedicated to developing motion tracking capabilities. When you're wearing a VR headset and looking down, the first thing you'll want to do is check how your hands look in the virtual world.
We've already seen LeapMotion's accessories—using infrared sensors to track your hand movements. We've also done some experiments tracking full-body motion with the Kinect2 camera. But currently, we have input devices from Oculus, Valve, and Sony.
Oculus Touch is a wireless controller designed to allow users to use it in virtual spaces as if they were using their own hands. For example, in shooting games, you can shoot by pulling the trigger. The controller also features an array of sensors to recognize actions such as tapping and waving.
This is remarkably similar to Valve's Lighthouse positioning and tracking system and the HTC Vive controller prototype. It includes two base stations in the room and fills the entire room with lasers. It accurately detects the position of your head and hands by observing the timing of the collisions between photocell sensors on your head and hands. Like the Oculus Touch, it also features distinctive physical buttons, and incredibly, it can track multiple users within the same space using two Lighthouse systems.
Other input methods include controllers borrowed from the Xbox controller or joysticks connected to a PC, voice control, smart gloves, and treadmills like the Virtuix Omni—which help you move more "gracefully" in the virtual world.
4. Eye tracking
Eye-tracking technology works by tracking our pupils. The algorithm adjusts the depth of field based on what we're looking at, creating a more immersive experience. For example, when you hold a finger up in front of your eye, the scenery in front of the finger blurs when you look at it, and blurs again when you look at the background – this is the effect of different depths of field. Eye-tracking technology knows where we're looking and simulates these changes in depth of field for a superior experience.
III. Future Development of VR
As VR hardware continues to expand and become more widespread, its applications will become increasingly broad. Previously, VR technology was used in aerospace education, providing pilots with realistic training experiences through simulation. Currently, VR technology is being adopted in real estate sales and theme park industries. In the future, it will also be used in education, industry, and other fields.
