Stereoscopic Viewing

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Stereoscopic Viewing

• Summarized by Geb Thomas

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Learning Objectives

• Learn how to calculate retinal disparity
• Understand the variety of cues that provide depth
  perception
• Understand the main stereo viewing devices and
  the differences between them
• Understand how to calculate important engineering
  parameters of stereoscopic display systems

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Computation of Retinal Disparity

• Cormack and Fox
• Images of objects nearer or farther than fixation
  fall on noncorresponding points on the retinas --
  retinal disparity
• Typically Assume that all points are on the
  horizontal fixation plane

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Fixation
Angle 1 ATNJAf/Df
Angle 2 ATNJ-Af/Df
Convergence Ang1 Ang2
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Target
Angle 3 ATNJAt/Dt
Angle 4 ATNJ-At/Dt
ct Ang3 Ang4
r angle cf - angle ct
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Stereoscopic Displays

• 3D visual display systems for virtual
  environments, McKenna and Zeltzer
• Display Characteristics
• 5 Display Designs

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Visual Cues and Display Attributes

• Field of View -- angle subtended by viewing
  surface (human eye 120x180)
• Spatial Resolution -- pixels (1280x1024 for many
  monitors human has fovial region for 1-2 deg,
  sensitivity of 2-4 cycles/degree 30 arc-sec)
• Refresh and Update rates -- critical fusion
  frequency 60Hz, 10-15Hz update rate for motion.

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Visual Cues and Display Attributes, Cont.

• Brightness -- from 1-1000 mL, response follows
  Webers law at 2 contrast. Most displays range
  from 2-8 to 20-60mL.
• Color -- Trichromatic color reproduction is
  somewhat noisy process, limits range of color
  reproduction.
• Information Rate and Bandwidth -- Human eye info
  rate -- 4.3Mbits/sec along nerve pathways,
  monitor has 2 Gbits/sec.

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Visual Cues and Display Attributes, Cont

• Viewing Zone/ Volume Extent
• Number of Views

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Depth Perception and Depth Cues

• Stereoscopic vrs. Autostereoscopic
• Oculomotor cues -- vergence and accomodation
• Binocular disparity
• Binocular depth resolution
• Motion parallax
• Pictorial Depth Cues -- Overlap, image size,
  linear perspective (position), texture gradient,
  aerial perspective, shading

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Stereoscopic Display
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Interactive Stereo
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Lenticular Screen/ Parallax Barrier
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Slice Stacking
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Computer-Generated Holography
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Learning Objectives

• Learn how to calculate retinal disparity
• Understand the variety of cues that provide depth
  perception
• Understand the main stereo viewing devices and
  the differences between them
• Understand how to calculate important engineering
  parameters of stereoscopic display systems

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