Outline

• How to Use Slidy
• What is Virtual Reality?
• Terminology Related to VR

Using Slidy

• The slides for this class are HTML files.
• They are made to look like slides using a Javascript called Slidy.
• The following keystrokes do useful things in Slidy:
  • h - help (see all the commands)
  • f - fullscreen (gets rid of the links at the bottom of the window
  • space - advance a slide
  • left/right arrows - forward or back a slide
  • up/down arrows - scroll within a slide
  • a - show all slides at once for printing

What is Virtual Reality?

• Virtual Reality is a rapidly developing field.
• In this class, I want to provide not only information about current tools and techniques of virtual reality, but also discuss things which are likely to stay the same for many years to come. aspects
• A good definition of virtual reality should fall into the latter category.
• Below are the definitions from the syllabus and from Wikipedia:
  • (Syllabus VR) Virtual Reality (VR) programming is the branch of computer science which studies the creation of immersive simulated environments. These environments can be similar to the real world or fantastical.
  • (Wikipedia VR) Virtual reality (VR) is an interactive computer-generated experience taking place within a simulated environment. It incorporates mainly auditory and visual feedback, but may also allow other types of sensory feedback like haptic. This immersive environment can be similar to the real world or it can be fantastical.
• Our textbook uses two examples of what we might want to try to simulate to present its definition:
  1. A human having an experience of flying over a virtual San Fransciso by flapping his own wings
  2. A mouse running on a freely rotating ball while exploring a virtual maze that appears on a projection screen around the mouse.

VR Examples

Books Definition of Virtual Reality

Definition. Virtual Reality is the induction of targeted behavior in an organism by using artificial sensory stimulation, while the organism has little or no awareness of the interference.

Breaking down the Components of the Definition

1. Targeted behavior. The organism is having an "experience" designed by the VR systems creator. For example, flying, walking, exploring, watching a movie, socializing with other organisms.
2. Organism. This could be a human or, as the second example illustrates, might be some other creature, such as a fruit fly, rodent, monkey, etc...
3. Artificial sensory stimulation. That is, the inputs to one or more senses are hijacked. For example, vision might be hijacked by showing images directly in front of the eye, or it might be hijacked by direct stimulation of the optic nerve. This is not so far-fetched in that we can already partially restore sight in blind people by direct stimulation of the optic nerve, so you could imagine just making virtual images using this.
4. Awareness. This means, while the experience is happening, the organism is relatively unaware that it is being fooled. It feels present in the virtual world.

Considering Boundaries of the Definition

• The two examples we have been considering meet the definition of VR.
• Any experience where we put on a VR head set and have a perceptual experience probably counts.
• But what about:
  • Listening to music on headphones?
  • Watching a movie?
  • Looking at a painting?
  • Reading a novel?
• Good arguments can be made either way about some of these border cases although they are not as direct in their stimulation of the organisms senses as we will typically consider.
• We will be somewhat flexible on the precise boundary of when a system becomes a VR system, but we want our systems to strive to be as convincing as possible to the target organism.

Who/What is being fooled?

• The notion of "fooling" an organism can be made concrete in terms of neurobiology.
• (Nitz 2010), (O'Keefe and Dosytovsky 1971) have shown that when an animal explores its environment, neural structures known as place cells are formed that encode spatial information about its surroundings.
• Each such cell is activated precisely when an organism returns to a particular location.
• There are also grid cells (Moser Kropff Moser 2008) which even encode locations in a manner similar to Cartesian coordinates.
• (Aghajan et al 2015) have shown that these structures are formed and activated even when have a modern VR experience.

Terminology Related to VR

• The term virtual reality dates to Immanuel Kant afterword of a book by the physician Sommerring in 1796.
• Its current use was popularized in the 1980s by Jaron Lanier and others.
• Another term which is almost synonymous with virtual reality is virtual environments.
• We will use virtual environments to mean a perceived environment which can be either synthetic or a replay of previously captured real environment.
• Augmented Reality refers to systems in which most of the visual stimuli are propagated directly throught glass or cameras to the eyes, and where some additional structures may appear superimposed onto the user's world.
• Mixed Reality refers to "realities" lying on the spectrum from pure VR to AR to normal reality.
• Telepresence refers to systems that enable users to feel like they are somewhere else in the world, for example, on board a drone in a remote location or in a surgery theater somewhere else, etc.
• Teleoperation refers to a telepresense system where the user is actually able to control some aspect of the remote setting. I.e., steer the drone, perform surgical cuts, etc.
• Perceptual Engineering refers to techniques for altering the user's perception reality for example ina VR system.

Interactivety in VR Systems

• Most VR systems involve interaction.
• If the sensory stimulation depends on the actions of the organism, then the VR system is said to be closed-loop; otherwise, it is said to be open-loop.
• In a closed loop system, movements of the body including eyes, head, hand, legs, heart rate, body temperature, skin conductance, etc, might affect the experience.
• Even watching a 180 degree stereoscopic movie might be to some degree closed-loop if gaze direction tracks in the scene.