Week 6 2 virtual displays virtual environments
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Week 6-2: Virtual Displays & Virtual Environments. Week 6 Topics. Lecture 6-1 3D Displays Navigation & Self-Motion Lecture 6-2 A Virtual Display for Speed Perception of Heading Perception of Time to passage. 36. 01. 02. 03. 10. 3750. 5620. 5. -5. -10.

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Week 6-2: Virtual Displays & Virtual Environments

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Week 6 2 virtual displays virtual environments

Week 6-2: Virtual Displays & Virtual Environments


Week 6 topics

Week 6 Topics

  • Lecture 6-1

    • 3D Displays

    • Navigation & Self-Motion

  • Lecture 6-2

    • A Virtual Display for Speed

    • Perception of Heading

    • Perception of Time to passage


Virtual displays for speed

36

01

02

03

10

3750

5620

5

-5

-10

Virtual Displays for Speed?


Virtual displays for speed1

Virtual Displays for Speed

  • Design Features

    • Flow vectors presented as moving arrows: speed and direction of arrows indicates magnitude and direction of speed error: arrows stop moving if pilot is at the target speed (prevents adaptation)

    • Overall size of arrows also changes as a function of speed -- arrows disappear if no speed error

      • size changes in steps: “attention grabbing”

      • reduces reliance on acceleration detection

    • Stimulus-Response (SR) compatibility: direction of arrows indicates direction of throttle movement to correct speed


Virtual displays for speed2

Virtual Displays for Speed

  • Testing the Virtual Display: Cox & Dyre (2000)

    • Dual Task: fly simulator through “waypoints” while simultaneously maintaining target altitude and speed

    • Single Tasks: autopilot controls flight-path or speed


Virtual displays for speed3

Virtual Displays for Speed

  • Measures:

    • Speed error

    • Altitude error

    • Missed waypoints

    • Subjective workload: NASA-TLX


Week 6 2 virtual displays virtual environments

Virtual Displays for Speed

  • Measures:

    • Speed error

    • Altitude error

    • Missed waypoints

    • Subjective workload: NASA-TLX


Virtual displays for speed4

Virtual Displays for Speed

  • Measures:

    • Speed error

    • Altitude error

    • Missed waypoints

    • Subjective workload: NASA-TLX


Perception of heading

Perception of Heading

  • Cues in Optical Flow

    • Expansion point or

      focus of radial outflow

      (Warren et al., 1988)

    • problem:

      eye movements

    • Differential Motion Parallax (Cutting, 1986)

    • Flow Symmetry (Dyre & Andersen, 1997)


Perception of heading1

Perception of Heading

Rotational Flow due to Eye Movement

Translational (Optical) Flow

Retinal Flow (Translation + Rotation)


Perception of heading2

Perception of Heading

  • Active closed loop control vs. Passive open-loop judgments

    • Active controllers (drivers) can perceive heading in a manner fundamentally different than passive viewers (passengers): Dyre, Warren, & Garness (1996)

      • Controllers -- more global?

      • Passengers -- more local?

    • Consistent with active-passive differences for motion sickness and spatial orientation

      • Armstrong (1939), Reason & Brand (1975)

      • Larish and Andersen (1995)


Perception of heading3

Perception of Heading

  • Field of view effects

    • Central visual field is necessary and sufficient for accurate judgments of heading

      • Warren & Kurtz (1992), Crowell & Banks (1993), Atchley & Andersen (1999)

    • Problems

      • used small fields of view (19” monitor) presented at different retinal eccentricities

      • controlled fixation

      • used discrete, open-loop judgments

      • did not present symmetrical fields of view to periphery


Perception of heading information basis

p(q, f)

f

a

r

H

q

Perception of Heading: Information Basis


Peripheral vision perception of heading

Peripheral Vision & Perception of Heading

  • Richman & Dyre (1999);

    Dyre, Morrow, and

    Richman (2000)

    • Used large,

      symmetrical fields

      of view for

      peripheral

      stimulation

      (90 x 34 deg of

      visual angle)

    • measured active control performance

    • free fixation: field of view mask or “porthole” yoked to observer’s gaze direction

    • Examined both yaw and pitch control


Apparatus for yoking gaze to display

Apparatus for Yoking Gaze to Display


Central peripheral full visual field

Central + Peripheral (Full) Visual Field

(image contrast inverted)


Central visual field condition

Central Visual Field Condition

(image contrast inverted)


Peripheral visual field condition

Peripheral Visual Field Condition

(image contrast inverted)


Central peripheral visual fields results

Central-Peripheral Visual Fields: Results

  • Results of

    • Peripheral visual fields benefit performance

    • Peripheral vision as good as central vision when peripheral regions of flow are orthogonal to control axis

Dyre, Morrow, and Richman (2000)


Perception of time to contact

Perception of Time to Contact

  • Time to Contact

    • specified by the size of an object scaled by its expansion rate (change in size)

      • size changes exponentially as an object approaches

        (object size)/(change in object size)

    • other factors that influence judgments

      • object size (large objects appear nearer)

      • Object expansion rate (dX/dt)

      • observer motion combined with object motion:

        lowers time to contact estimates


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