HFE 760 Virtual Environments

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HFE 760 Virtual Environments

• Winter 2000
• Jennie J. Gallimore
• Jgalli_at_cs.wright.edu

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HFE 760 Virtual Environments

• Course Objective
• To acquire an understanding of human factors
  issues and problems related to the development of
  virtual environment systems.
• By the end of the quarter students will have
• an understanding of VE technologies,
• understanding of research needs and issues,
• experience creating a VE
• experience conducting a VE research project

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Introduction/Definitions

• What is a virtual environment?

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Definitions (from Chapter 1)

• Virtual Environment - representation of a
  computer model (or database) that can be
  manipulated in an interactive way by
  participants.
• Virtual Image - visual, auditory, tactile and
  kinesthetic stimuli conveyed so that they appear
  to originate from a 3-D space surrounding the
  participant.
• Virtual Interface - System of transducers, signal
  processor, hardware, software creating an
  interactive medium to
• 1) convey information to senses,
• 2) monitor the psychomotor and physiological
  behavior of participant.

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Typical interface - Desktop metaphor

• To interact requires three cognitive models
• 1) model of immediate environment.
• 2) model of functionality of medium (e.g.
  Monitor and keyboard).
• 3) model of the message and it's heuristics
  conveyed through the medium.

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Immersed VE

• We become part of the message, draw on a single
  model of the new environment. Given we are in the
  environment, should be able to use natural
  semantics as if interacting with physical world.

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Ideal Medium

• Should be configured to match sensory and
  perceptual capabilities of humans and the message
  should be organized to achieve a match between
  human's mental model of the system and machine
  interpretation and representation of that system.
  
• Table 1-1 (p7) provides examples of attributed of
  an ideal medium.

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Issues and Problems (Pg. 11)

• Theoretical basis for work in VE, develop
  conceptual models to assist designers of virtual
  worlds.
• Solid understanding of human factors design
  implications.
• Development of dependent measures to determine
  goodness of VEs.
• Physiological and behavior tracking of
  participants.

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Issues and Problems Cont. (Pg. 11)

• Affordable, light weight systems.
• Hardware architecture, rapid image generation
  methods,
• Software infrastructure and tools for
  constructing, managing, interacting in VE.
• Need for languages, spatial and state
  representations, and interactive heuristics for
  constructing virtual worlds.

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Three Components of an Environment (Ellis,
Chapter 2)

• Content
• Geometry
• Dynamics

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Content

• Object and actors - described by characteristic
  vectors (position, orientation, velocity,
  acceleration, color, texture, energy) i.e. a
  description of the properties of the objects.
  The characteristics that are common to all
  objects and actors is called the position vector.
• Actors - are different from objects in that they
  have the capacity to initiate interactions with
  objects. Actors store energy of information and
  control the release of the energy or information
  after a period of time.
• Examples Self - provides a point of view from
  which the environment may be constructed.
• E.g. balls on a billiard table are content
  (objects) and the cue is an actor.

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Geometry

• Dimensionality - number of independent
  descriptive terms needed to specify the position
  vector for every element in the environment (e.g.
  where, when, color, etc..)
• Metrics- systems of rules that may be applied to
  the position vector to establish order, and the
  concept of geodesic (or loci of minimal distance)
  paths between points in the space. (E.g. Minimum
  distance between objects/actors)
• Extent - range of possible values for the
  elements of the position vector. (E.g. if color
  is a characteristic of the position vector, what
  is the possible range of colors?)

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Dynamics

• Rules of interaction among contents describing
  behavior as energy or information is exchanged.
• E.g. (Equations for swing the golf club or
  baseball bat given current states)

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Virtualization (ELLIS)

• "the process by which a human viewer interprets a
  patterned sensory impression to represent an
  extended object in an environment other than that
  in which it physically exists"
• E.g. virtual image in optics

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Levels of virtualization

• virtual space - viewer perceives a 3-D layout
  when viewing a flat surface
• virtual image - perception of an object in depth
  in which accommodative, vergence, and
  stereoscopic disparity are present, but not
  necessarily consistent
• virtual environments - added elements of
  observer-slaved motion parallax, depth of focus
  variation, wide field-of-view. Synthesized to
  provide stimulation of psychological and
  physiological reflexes.

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Viewpoints

• Egocentric - sensory environment is constructed
  form viewpoint of the user (compensatory)
• Exocentric - environment is viewed from a
  position other than where the user is (e.g.
  Bird's eye view, secondary viewer so can see
  yourself in the world) (pursuit)