Module 1 of 4: XR Terminology & Applications

本模块将建立围绕 XR 的不同概念，并提供相关技术的简要概述。 了解 AR、VR 和 MR 的潜力和局限性的关键是了解它们各自工作方式和用途的差异。

VR and AR

Virtual Reality. Replacing the reality around the user. We do this by providing a computer generated virtual environment. So there is no more real world view that is only the virtual view.
Summarize:
VR: Replaces Reality, Computer-generated, virtual environment.

Augmented Reality. on the other hand, enhances reality. So the user actually sees both the real world and the virtual world. They’re like merged together.
Summarize:
virtual world merged with physical world. real+virtual, composite view.

VR is defined in terms of three main charactertics

1. Virtual reality emphasizes autonomy and agency, so the user at all times stays in control.
2. Virtual reality provides natural interaction, using gestures with the controller, hand or fingers and speech as input.
3. Virtual reality gives us a sense of presence, the feeling of being there. So as we enter the virtual world, we are being immersed.

AR is defined in terms of three main charactertics

1. Augmented reality combines real and virtual objects to produce a conposite view. So it is not just objects, it can also be audio information overlaid.
2. Augmented reality interactive in real time. It support both explicit and implicit interaction.
3. Augmented reality is registered in 3D. We need to do this in order to align the real and virtual objects, specially in the physical world. They appear as if they were part of the same world.

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Mixed Reality

什么是Mixed Reality

如上图所示，Real Environment 就是现实环境，Virtual Environment 就是虚拟环境。
AR可以分为两个，一个叫做Augmented Reality AR，为虚拟和现实结合的产物，但是更偏向现实；另一个叫做Augmented Virtuality AV，同样也为虚拟和现实结合的产品，但是更偏向虚拟。
而 Mixed Reality，即混合现实，则是物理世界和虚拟世界的混合，具有不同程度的增强，包含刚才所说的AR与AV。

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XR

XR = Extended Reality (X is wildcard for A, V, or M)

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XR technology landscape

Four Classes of XR Technology

fig. Some Device of VR, AR

fig. Some platform of VR, AR