4. The Physical World and the Perceptual World
• Physical World - exist outside observer
Wednesday, 4 June 14
5. The Physical World and the Perceptual World
• Physical World - exist outside observer
• Perceptual World
Wednesday, 4 June 14
6. The Physical World and the Perceptual World
• Physical World - exist outside observer
• Perceptual World
• Experienced by the observer
Wednesday, 4 June 14
7. The Physical World and the Perceptual World
• Physical World - exist outside observer
• Perceptual World
• Experienced by the observer
• Produced by activity in eye-brain system - when - patterned light simulates
the eye of observer
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8. The Physical World and the Perceptual World
• Physical World - exist outside observer
• Perceptual World
• Experienced by the observer
• Produced by activity in eye-brain system - when - patterned light simulates
the eye of observer
• Consist of - view at a given moment
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9. The Physical World and the Perceptual World
• Physical World - exist outside observer
• Perceptual World
• Experienced by the observer
• Produced by activity in eye-brain system - when - patterned light simulates
the eye of observer
• Consist of - view at a given moment
• 4D World - “3D Space” + Time
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13. Geometrical Relationships
• Physical Space
• Object can be displaced / rotated
without deformation
• Follows Euclidean Geometry -
Parallel Postulate - Parallel Lines do
not meet
Wednesday, 4 June 14
14. Geometrical Relationships
• Physical Space
• Object can be displaced / rotated
without deformation
• Follows Euclidean Geometry -
Parallel Postulate - Parallel Lines do
not meet
• Points in space can be assigned
coordinates in Cartesian coordinate
system and distance between points
can be measured w.r.t origin
Wednesday, 4 June 14
15. Geometrical Relationships
• Physical Space
• Object can be displaced / rotated
without deformation
• Follows Euclidean Geometry -
Parallel Postulate - Parallel Lines do
not meet
• Points in space can be assigned
coordinates in Cartesian coordinate
system and distance between points
can be measured w.r.t origin
• Perceptual (Visual) Space
Wednesday, 4 June 14
16. Geometrical Relationships
• Physical Space
• Object can be displaced / rotated
without deformation
• Follows Euclidean Geometry -
Parallel Postulate - Parallel Lines do
not meet
• Points in space can be assigned
coordinates in Cartesian coordinate
system and distance between points
can be measured w.r.t origin
• Perceptual (Visual) Space
• Geometry of Physical space w.r.t.
Perceiver
Wednesday, 4 June 14
17. Geometrical Relationships
• Physical Space
• Object can be displaced / rotated
without deformation
• Follows Euclidean Geometry -
Parallel Postulate - Parallel Lines do
not meet
• Points in space can be assigned
coordinates in Cartesian coordinate
system and distance between points
can be measured w.r.t origin
• Perceptual (Visual) Space
• Geometry of Physical space w.r.t.
Perceiver
• Direction and Distance in Polar
Coordinates
Wednesday, 4 June 14
18. Geometrical Relationships
• Physical Space
• Object can be displaced / rotated
without deformation
• Follows Euclidean Geometry -
Parallel Postulate - Parallel Lines do
not meet
• Points in space can be assigned
coordinates in Cartesian coordinate
system and distance between points
can be measured w.r.t origin
• Perceptual (Visual) Space
• Geometry of Physical space w.r.t.
Perceiver
• Direction and Distance in Polar
Coordinates
• By specifying an origin that
corresponds to a perceiver - visual
space can be measured in terms of
angular direction and radial distance
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21. • Relationships among Spaces - Perceived and Physical
• To maintain important distinction between
Wednesday, 4 June 14
22. • Relationships among Spaces - Perceived and Physical
• To maintain important distinction between
• physical objects (or scenes) and
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23. • Relationships among Spaces - Perceived and Physical
• To maintain important distinction between
• physical objects (or scenes) and
• pattern of reflected light impinging on the retinal surface
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24. • Relationships among Spaces - Perceived and Physical
• To maintain important distinction between
• physical objects (or scenes) and
• pattern of reflected light impinging on the retinal surface
• Physical Objects (or scenes) are described as distal stimuli and
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25. • Relationships among Spaces - Perceived and Physical
• To maintain important distinction between
• physical objects (or scenes) and
• pattern of reflected light impinging on the retinal surface
• Physical Objects (or scenes) are described as distal stimuli and
• Impinging Patterns of light are described as proximal stimuli
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26. • Relationships among Spaces - Perceived and Physical
• To maintain important distinction between
• physical objects (or scenes) and
• pattern of reflected light impinging on the retinal surface
• Physical Objects (or scenes) are described as distal stimuli and
• Impinging Patterns of light are described as proximal stimuli
• Perception refers to the process or act of perceiving, whose
content is the percept, the conscious experience of the distal
object or scene.
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28. • Distal objects and scenes can be observed directly
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29. • Distal objects and scenes can be observed directly
• Perception cannot be observed directly
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30. • Distal objects and scenes can be observed directly
• Perception cannot be observed directly
• Proximal stimulus patterns can be observed by
Wednesday, 4 June 14
31. • Distal objects and scenes can be observed directly
• Perception cannot be observed directly
• Proximal stimulus patterns can be observed by
• projecting light from distal stimuli
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32. • Distal objects and scenes can be observed directly
• Perception cannot be observed directly
• Proximal stimulus patterns can be observed by
• projecting light from distal stimuli
• onto a surface - a screen or projection place that represents the retinal surface
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33. • Distal objects and scenes can be observed directly
• Perception cannot be observed directly
• Proximal stimulus patterns can be observed by
• projecting light from distal stimuli
• onto a surface - a screen or projection place that represents the retinal surface
• Each component of perceptual act - distal stimulus, proximal stimulus, percept,
response - can be described geometrically
Wednesday, 4 June 14
34. • Distal objects and scenes can be observed directly
• Perception cannot be observed directly
• Proximal stimulus patterns can be observed by
• projecting light from distal stimuli
• onto a surface - a screen or projection place that represents the retinal surface
• Each component of perceptual act - distal stimulus, proximal stimulus, percept,
response - can be described geometrically
• The relationship between adjacent components in a sequence may be described
by mapping the geometry of one component into geometry of the next
component
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37. Distal - Proximal Relationships
• Projective Geometry: Geometrical Optics
• The light falling on an eye can come
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38. Distal - Proximal Relationships
• Projective Geometry: Geometrical Optics
• The light falling on an eye can come
• directly from an emitting source or
Wednesday, 4 June 14
39. Distal - Proximal Relationships
• Projective Geometry: Geometrical Optics
• The light falling on an eye can come
• directly from an emitting source or
• after being refracted through a medium like air, water
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40. Distal - Proximal Relationships
• Projective Geometry: Geometrical Optics
• The light falling on an eye can come
• directly from an emitting source or
• after being refracted through a medium like air, water
• The 2D pattern of light reflected to an eye from 3D arrangement of objects
in the world is described by projective geometry
Wednesday, 4 June 14
41. Distal - Proximal Relationships
• Projective Geometry: Geometrical Optics
• The light falling on an eye can come
• directly from an emitting source or
• after being refracted through a medium like air, water
• The 2D pattern of light reflected to an eye from 3D arrangement of objects
in the world is described by projective geometry
• We apply geometrical analysis to light - it is called as Geometrical Optics
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43. • To study perception - it is necessary to consider
only the rays that enter the eye of a viewer.
Wednesday, 4 June 14
44. • To study perception - it is necessary to consider
only the rays that enter the eye of a viewer.
• Fig. shows the distal-proximal realtions for a
single eye
Wednesday, 4 June 14
45. • To study perception - it is necessary to consider
only the rays that enter the eye of a viewer.
• Fig. shows the distal-proximal realtions for a
single eye
• The viewer is looking at house - a distal object
Wednesday, 4 June 14
46. • To study perception - it is necessary to consider
only the rays that enter the eye of a viewer.
• Fig. shows the distal-proximal realtions for a
single eye
• The viewer is looking at house - a distal object
• Light is reflected everywhere - but the perceiver is simulated only by light that - enters the
eye
Wednesday, 4 June 14
47. • To study perception - it is necessary to consider
only the rays that enter the eye of a viewer.
• Fig. shows the distal-proximal realtions for a
single eye
• The viewer is looking at house - a distal object
• Light is reflected everywhere - but the perceiver is simulated only by light that - enters the
eye
• Light is represented by the rays that converge toward the nodal point of the eye and simulate
cells on the retina of the viewer.
Wednesday, 4 June 14
48. • To study perception - it is necessary to consider
only the rays that enter the eye of a viewer.
• Fig. shows the distal-proximal realtions for a
single eye
• The viewer is looking at house - a distal object
• Light is reflected everywhere - but the perceiver is simulated only by light that - enters the
eye
• Light is represented by the rays that converge toward the nodal point of the eye and simulate
cells on the retina of the viewer.
• The pattern of light simulating cells on retina constitutes the proximal stimulus
Wednesday, 4 June 14
49. • To study perception - it is necessary to consider
only the rays that enter the eye of a viewer.
• Fig. shows the distal-proximal realtions for a
single eye
• The viewer is looking at house - a distal object
• Light is reflected everywhere - but the perceiver is simulated only by light that - enters the
eye
• Light is represented by the rays that converge toward the nodal point of the eye and simulate
cells on the retina of the viewer.
• The pattern of light simulating cells on retina constitutes the proximal stimulus
• inverted w.r.t. orientation of distal object
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53. • Proximal Geometry - Geometry of Perspective
• represented in a hypothetical projection
plane erected b/w the viewer
and the distal stimulus
Wednesday, 4 June 14
54. • Proximal Geometry - Geometry of Perspective
• represented in a hypothetical projection
plane erected b/w the viewer
and the distal stimulus
• In above figure, the projection is on frontoparallel plane or picture
plane - a plane that is perpendicular to line of sight of the viewer
Wednesday, 4 June 14
55. • Proximal Geometry - Geometry of Perspective
• represented in a hypothetical projection
plane erected b/w the viewer
and the distal stimulus
• In above figure, the projection is on frontoparallel plane or picture
plane - a plane that is perpendicular to line of sight of the viewer
• the upright pattern in proximal stimulus is described by 2D
geometry of perspective
Wednesday, 4 June 14
56. • Proximal Geometry - Geometry of Perspective
• represented in a hypothetical projection
plane erected b/w the viewer
and the distal stimulus
• In above figure, the projection is on frontoparallel plane or picture
plane - a plane that is perpendicular to line of sight of the viewer
• the upright pattern in proximal stimulus is described by 2D
geometry of perspective
• In this pattern, the size of a distal object is represented according
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58. “The Problem ofVisual Space Perception”
• To relate - the experienced qualities - of - visual space to specific
aspects of simulation - and - to processes occurring in the visual
space system
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59. “The Problem ofVisual Space Perception”
• To relate - the experienced qualities - of - visual space to specific
aspects of simulation - and - to processes occurring in the visual
space system
• To simplify these tasks of identifying these components - visual
space perception is divided into two different ways
Wednesday, 4 June 14
60. “The Problem ofVisual Space Perception”
• To relate - the experienced qualities - of - visual space to specific
aspects of simulation - and - to processes occurring in the visual
space system
• To simplify these tasks of identifying these components - visual
space perception is divided into two different ways
• Binocular and Monocular Perception
Wednesday, 4 June 14
61. “The Problem ofVisual Space Perception”
• To relate - the experienced qualities - of - visual space to specific
aspects of simulation - and - to processes occurring in the visual
space system
• To simplify these tasks of identifying these components - visual
space perception is divided into two different ways
• Binocular and Monocular Perception
• Static and Kinetic Analysis
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64. Visual Directions
• Visual directions experienced when viewing a
scene with two eyes
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65. Visual Directions
• Visual directions experienced when viewing a
scene with two eyes
• Eyes are in different positions in space
Wednesday, 4 June 14
66. Visual Directions
• Visual directions experienced when viewing a
scene with two eyes
• Eyes are in different positions in space
• When looking at a single point, the two eyes
must be oriented in slightly different directions
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69. Monocular Localization of Directions
• MonocularVisual Field
• The portion of the world that is visible to a single
stationary eye defines the monocular visual field
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70. Monocular Localization of Directions
• MonocularVisual Field
• The portion of the world that is visible to a single
stationary eye defines the monocular visual field
• Perimetry
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71. Monocular Localization of Directions
• MonocularVisual Field
• The portion of the world that is visible to a single
stationary eye defines the monocular visual field
• Perimetry
• Field of monocular vision
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72. Monocular Localization of Directions
• MonocularVisual Field
• The portion of the world that is visible to a single
stationary eye defines the monocular visual field
• Perimetry
• Field of monocular vision
• Blind spot
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79. • Objective Directions:Visual Lines
• Visual Line - locus of distal points that stimulate a given point on
the retina of a single eye
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80. • Objective Directions:Visual Lines
• Visual Line - locus of distal points that stimulate a given point on
the retina of a single eye
• PrincipalVisual Line (PVL) - locus of distal points that stimulate the
center of foveola of a single eye
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81. • Objective Directions:Visual Lines
• Visual Line - locus of distal points that stimulate a given point on
the retina of a single eye
• PrincipalVisual Line (PVL) - locus of distal points that stimulate the
center of foveola of a single eye
• Line passing through the center of the foveola, the nodal point of
the eye and the fixated point is Visual Axis
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82. • Relationship between distal points and their representation in the
proximal stimulus for a single eye
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85. • Subjective Directions: Visual directions
• Perceived visual directions are the subjective directions of points
in space (up, down, left, right)
Wednesday, 4 June 14
86. • Subjective Directions: Visual directions
• Perceived visual directions are the subjective directions of points
in space (up, down, left, right)
• When eye is directed at a given point, the image of the point falls
on the center of the fovea
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87. • Subjective Directions: Visual directions
• Perceived visual directions are the subjective directions of points
in space (up, down, left, right)
• When eye is directed at a given point, the image of the point falls
on the center of the fovea
• The subjective direction associated with this fixation is called
PrincipalVisual Direction (pvd).
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88. • Proximal - perceptual relations described by visual directions.
• Perceived directions are described relative to the principal visual direction (pvd)
• Point A appears to be ߺ to the left and øº above pvd
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91. • Vergence Movements
• Conjunctive eye movements that maintain a constant
convergence angle
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92. • Vergence Movements
• Conjunctive eye movements that maintain a constant
convergence angle
• Vergence Movements are disjunctive eye movements in which
the convergence angle changes i.e. the eye muscle move the
eyes equally inward or outward.
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93. • tan y/2 = A / 2D
• ~ y = A/D for small y in radians
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