Depth Perception

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Depth Perception

• Kimberley A. Clow
• kclow2_at_uwo.ca
• http//instruct.uwo.ca/psychology/215a-570

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Outline

• Oculomotor Cues
• Pictorial Cues
• Motion Based Cues
• Stereopsis
• Development of Depth Perception
• Effects of Experience

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Types
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Importance

• Recognition of location in space is essential for
  almost all activities
• navigating/avoiding objects
• jumping
• catching/throwing
• reaching/grasping
• size judgements and recognition
• As a result, many redundant systems available for
  assessing depth and distance

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How Do We Perceive Depth?
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Oculomotor Cues
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Accomodation
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Convergence
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Pictorial Cues
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Occlusion
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Height in Visual Field
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Moon Illusion
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Possibility
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Relative Size
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How it works
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Can Create Illusions...
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Excuse me for shouting I thought you were
farther away.
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Which is Bigger?
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Familiar Size
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Effects of Familiar Size
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Atmospheric Haze
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Linear Perspective
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Which Line is Longer?
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Texture Gradient
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Texture Discontinuities
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Shading
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Pictorial Cues Together
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Illusion
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Explanation
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Motion Based Cues

• These cues depend on
• Geometric changes in the scene
• Effects of self-motion
• Movement through the visual field

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Motion Parallax
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Biological Motion
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Optic Flow
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Binocular Cues

• Two eyes
• Slightly displaced images in each eye
• Info about relative depth
• Based on the geometry of the images reaching the
  eye

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Important Terms
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Retinal Disparity
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Example
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Crossed Uncrossed
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Diplopia
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Stereopsis
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Physiological Basis

• How can cortical neurons process disparity
  information?
• Cortical neurons that code retinal disparity
• Respond based on the positions of the images on
  the two retinae

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Example
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Motion Illusion
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Size Constancy

• Why does someone walking away NOT appear to
  shrink?

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The Holway-Boring Experiment
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Which Line is Longer?
1?
2?
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Explanation
1
2
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Development
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The Effects of Experience