modeling methods, performance technology, human-
computer interaction, and equipment, which are three
major categories.
The technology of superimposing 3D virtual
objects into real-world displays is called AR. The
synthesis of the real world and virtual environment
reduces the workload of 3D modeling, improves user
experience and credibility with the help of real scenes
and objects, and promotes the further development of
VR technology. AR technology is "real with virtual',
the image captured by the camera truly reflects the
real scene, which can reduce the modeling and
rendering workload of the scene, providing a
lightweight and realistic technology.
The technical characteristics of AR can be
separated from the following three points: mixing
virtual and real environments; real-time interaction;
and three-dimensional registration.
The key technologies of VR/AR contain mainly
the following:
Environment Modeling Technology:
That is, the establishment of the virtual
environment, the purpose is to obtain the actual
three-dimensional data of a three-dimensional
environment, and according to the needs of the
application, use the acquired three-dimensional
data to establish the corresponding virtual
environment model.
At present, the study of the physical
representation of virtual objects and their physical
models is mainly focused on kinematics and
dynamics. Physical models are available only for
particle systems, spring models, smoothed
particle hydrodynamics methods, and a few
others. Many physical characteristics of matter
(such as material characteristics), physical
phenomena such as explosions and cuts, realistic
representation of physical characteristics, and
interaction responses of material objects such as
flexible, viscous, plastic, flow, gas, and field in
real-time, there are many theoretical problems.
The balance between real-time and realism for
specific applications is also a problem to be
considered because of the huge computational
effort of the physical model.
With the continuous expansion of VR application
fields, virtual human manipulating entities (e.g.,
aircraft, vehicles, etc.) becomes an important part
of VR systems, and the behavior of these
intelligence makes the three I (immersion,
interaction, imagination) characteristics of VR
systems develop to four I, i.e. intelligence. The
solution to this kind of problem depends on the
development of artificial intelligence technology
and human brain science.
Haptic Feedback Technology:
In VR systems, users can manipulate virtual
objects directly and feel the reaction force of the
virtual objects, thus creating a sense of
immersion.
There are still a large number of problems with the
way and mechanism of force/haptic realistic
perception between human and virtual objects and
their devices, especially the sense of flexibility; in
addition, the study of new perceptual channels,
such as the sense of temperature and humidity,
smell/taste, etc., is a problem area that requires
multidisciplinary cross research to solve.
Interaction Technology:
Human-computer interaction in VR technology
goes far beyond the traditional mode of keyboard
and mouse, using complex sensor devices such as
digital helmets and digital gloves, as well as three-
dimensional interaction technology with voice
recognition and voice input technology to become
an important means of human-computer
interaction.
The spatial calculation of virtual scenes in head-
mounted displays, including the real-time
accurate tracking and positioning of the
experiencer's head and position, as well as the
location calculation and real-time performance of
virtual objects in real space in AR head-mounted
displays are issues that need further research.
Related to this, virtual-real fusion is one of the
basic problems of AR, including the fusion of
graphic objects and video images in video-based
AR display, and the fusion of graphic objects and
real scenes in optical perspective-based AR
display, and many problems are yet to be solved.
Meanwhile, the outdoorization of optical
perspective AR, including the fusion of reality and
reality in large outdoor scenes, is a direction to be
explored.
Mobile Terminal and Internet-Based VR:
Mobile terminal and Internet-based VR have
great potential for development. For the former,
low computing and low storage VR technology,
cloud VR technology, low latency big data
transmission and new interaction are innovative
technology directions. The latter requires full-
screen 3D drawing, VR device access with more
appropriate human-computer interaction
mechanisms, and new browser standards. web VR
will bring change and disruptive impact on
existing browsers and mail systems, etc., and
become the new entrance to the Internet.