Depth Cues

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(No Transcript)
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Depth Cues

• Pictorial Depth Cues aspects of 2D images that
  imply depth
• Physiological Depth Cues Proprioception in
  ocular muscles indicates accommodation and
  convergence
• Motion Depth Cues foreground and background
  move in opposite directions
• Stereoscopic Depth Cues disparity between two
  retinal images indicates distance

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Pictorial Depth Cues

• Texture gradient

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Pictorial Depth Cues

• Height in the plane

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More Depth Cues

• Pictorial Depth Cues
• Physiological Depth Cues
• Motion Parallax
• Stereoscopic Depth Cues

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Physiological Depth Cues

• Two Physiological Depth Cues
• accommodation
• convergence

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Physiological Depth Cues

• Accommodation

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Physiological Depth Cues

• Convergence

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Physiological Depth Cues

• Convergence
• small angle of convergence far away
• large angle of convergence near
• What two sensory systems is the brain
  integrating?
• What happens to images closer or farther away
  from fixation point?

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Physiological Depth Cues

• Convergence and accommodation are reflexively
  linked

Under what circumstances might this be a problem?
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Motion Depth Cues

• Motion
• Parallax

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Motion Depth Cues

• Parallax

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Motion Depth Cues

• Parallax
• points at different locations in the visual field
  move at different speeds depending on their
  distance from fixation

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Motion Depth Cues

• Parallax

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Seeing in Stereo
Seeing in Stereo
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Seeing in Stereo
Its very hard to read words if there are
multiple images on your retina
Its very hard to read words if there are
multiple images on your retina
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Seeing in Stereo
Its very hard to read words if there are
multiple images on your retina
Its very hard to read words if there are
multiple images on your retina
But how many images are there on your retinae?
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Binocular Disparity

• Your eyes have a different image on each retina
• hold pen at arms length and fixate the spot
• how many pens do you see?
• which pen matches which eye?

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Binocular Disparity

• Your eyes have a different image on each retina
• now fixate the pen
• how many spots do you see?
• which spot matches which eye?

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Binocular Disparity

• Binocular disparity is the difference between
  the two images

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Binocular Disparity

• Binocular disparity is the difference between
  the two images
• Disparity depends on where the object is relative
  to the fixation point
• objects closer than fixation project images that
  cross
• objects farther than fixation project images that
  do not cross

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Binocular Disparity

• Corresponding retinal points

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Binocular Disparity

• Corresponding retinal points

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Binocular Disparity

• Corresponding retinal points

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Binocular Disparity

• Corresponding retinal points

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Binocular Disparity

• Points in space that have corresponding retinal
  points define a plane called the horopter

The Horopter
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Binocular Disparity

• Points not on the horopter will be disparate on
  the retina (they project images onto
  non-corresponding points)

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Binocular Disparity

• Points not on the horopter will be disparate on
  the retina (they project images onto
  non-corresponding points)
• The nature of the disparity depends on where they
  are relative to the horopter

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Binocular Disparity

• points nearer than horopter have crossed
  disparity
• points farther than horopter have uncrossed
  disparity

The Horopter
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Binocular Disparity

• Why dont we see double vision?

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Binocular Disparity

• Why dont we see double vision?
• Images with a small enough disparity are fused
  into a single image