Virtual Reality Technology Report

1 Overview

1.1 Introduction to Virtual Reality Technology

Virtual reality technology is a kind of computer technology that can create and experience the virtual world. It uses computers to generate a simulation environment. It is a system simulation of multi-source information fusion and interactive 3D dynamic scene and entity behavior, Helmet, data glove and other professional equipment, allowing users to enter the virtual space, real-time perception and operation of a variety of objects in the virtual world, so as to get through the visual, tactile and auditory real immersive experience. Virtual reality technology is an important direction of simulation technology. It is a challenging cross technology that is a combination of simulation technology and computer graphics, human interface technology, multimedia technology, sensor technology and network technology.

 

2. Virtual Reality Technology principles and key technologies

2.1 Virtual Reality Technology Principles

(1) Display principle: Due to the different positions of the two eyes of the people, the images obtained by people looking around are also slightly different. These images are integrated in the human brain to form a whole scene of the surrounding things. Including distance information. According to this principle, binocular stereo vision is adopted in the VR system. The system uses a single display. However, when the user brings in special glasses, one eye can only see odd-numbered frame images and the other eye can only see Even frame images, odd, even between different frames that is, the parallax generated a sense of three-dimensional.

(2) sound principle: in the horizontal direction, people rely on the phase difference of sound and intensity difference to determine the direction of the sound, because the sound reaches the ears of the time or distance are different. The common stereo effect is achieved by listening to different sounds recorded in different locations on the left and right ears, so there is a sense of direction. In real life, when the head is turned, the direction of the sound you hear changes. However, in VR systems, the direction of the sound is not related to the movement of the user's head.

(3) Feeling feedback principle: In a VR system, people can see a cup, you can try to seize it, but can not grasp the feeling of the cup, only through the cup surface. A common device for solving this problem is to mimic tactile sensation by installing some vibrating contacts in the inner layer of the glove.

(4) phonetics principle: In the VR system, the voice input and output is also very important. This requires that the virtual environment understand people's language and interact with people in real time. It is quite difficult for computers to recognize human voice because of their "polygamy" and complexity of speech and natural language signals. The use of human natural language as a computer input There are currently two problems, the first is the efficiency issue, in order to facilitate computer understanding, the input voice may be very verbose. Followed by the correctness of the problem, the computer to understand the pronunciation of the contrast is matched, but no one's intelligence.

 

2.2 The key technologies of virtual reality

The basic features of virtual reality technology include the three most prominent features: interactive, immersive and imaginative. It was presented by the U.S. scientists Burdea G. and Philippe Coiffet at the 1993 World Electronics Annual Meeting. based on the immersive and interactive characteristics of VR virtual reality and the restriction of network transmission rate, how to realize the real-time and realistic dynamic environment is the guarantee of the virtual reality system. The following describes the technical implementation of the correct implementation of the virtual reality system is the key technology.

(1) VR rendering technology. A typical rendering technology is Nvidia introduced MRS multi-resolution shader rendering technology, the overall rendering sub-regional model, according to the central to the two sides using different resolution methods to reduce GPU rendering pressure. Foveated rendering, developed by a domestic company, mainly focuses on the rough rendering of multi-resolution shader rendering and fine-grained tracking.

(2) VR screen display technology. The VR display screen mainly includes two types of OLEDs and LCDs. OLEDs use organic light-emitting diodes (OLEDs) to achieve low afterglow, but there is a problem of dividing the grids between the pixels. The LCD uses a rear-projection light source to display each pixel Passive light, relatively easy to produce serious afterglow phenomenon.

(3) VR positioning technology. VR immersive experience comes mainly from the three-dimensional display and precise positioning technology, allowing users to generate their own body movement into VR virtual environment, the main positioning technologies are: infrared positioning, laser positioning, visible light positioning, Bluetooth low energy positioning and so on.