[MUSIC] In this video we will discuss what virtual reality, or VR, is. The definition of VR can be very broad. I've come across situations where people referred to VR as anything that happens in the digital world. This includes things like online banking, online shopping, and social networking. But more often, the term VR has been used to refer more specifically to computer-generated graphical representations of the real or fantasy world. This definition includes any games, films, and advertisements where computer graphics are used. And you normally view them on your phone, on TV, or in the cinema. However, recently more and more people have started to use the term VR exclusively for the immersive experience supported by a relatively small range of VR displays. Including the CAVE-like system on the left and Oculus Rift headset on the right. The experience delivered by these devices can be very different from watching TV at home or going to the cinema. And in order to describe these experiences, we often use terms such as immersive, engaging, and interactive. This immersive and engaging experience will be new to most people, but a vision of it has existed for over 50 years. In this course, we will use the more recent definition for Fred Brooks in 1999. He defined VR as the experience in which the user is effectively immersed in a responsive virtual world. In particular, he pointed out that this implies the user has dynamic control of their viewpoint, which is something at the heart of any VR display system. So how is immersive VR different from other types of media, for instance, TV, cinema, 3D TV and 3D cinema? Essentially, three things make VR more immersive than other types of media, 3D Stereovision, user dynamic control of viewpoint, and a surrounding experience. Let's explain this with a standard VR headset, in this case, an Oculus Rift. In this video clip, you can see a participant wearing an Oculus Rift. I have a similar device here. So first of all, with these devices you have two displays, one in front of each eye, and the image on each display is slightly different from the other. Just like how we perceive the real world with both eyes, this gives you 3D stereo vision. It is similar to a 3D cinema experience. Secondly, these devices give the user dynamic control of their viewpoint. As we mentioned in the VR definition by Fred Brooks, this means that the experience is more real than in a 3D cinema. In a 3D cinema, you can have hundreds of viewers looking at one big display. But here, the display is updated according to the exact viewpoint of one specific user. This is achieved through a built-in head-tracking device in the head-mounted display, or HMD. Finally, with these devices your full visual perception is surrounded by the device. If you compare watching a film on a small TV to watching the same movie in a cinema or in an IMAX cinema, where you have a massive screen, the experiences can be very different. Basically, the more of your field of view is covered by the screen, the more immersed you will feel. The screen size of these headsets might be tiny, but there is no escape. In a cinema when you look around, you can see your friend sitting next to you. But with these headsets, you are trapped. When you look around in this headset, you still see images from the virtual world rather than the real world. The interesting thing is that this kind of experience is overwhelming and persistent. It doesn't diminish over time. I've been working with these immersive VR devices since 2005, but I still have the illusion. For instance, once I had a device on and a colleague was talking to me from my right. So automatically, I turned right to reply to her. And obviously with a headset on, I couldn't see her. And for about half a second, I was really puzzled. And I thought, where did she go? The effect of these devices can often be surprising and even shocking to the participants. This is something I have frequently observed in hundreds of experiments using these devices. [MUSIC]
