Visual space perception

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Set of slides used on one of my presentations for explaining - Visual Space Perception.

Set of slides used on one of my presentations for explaining - Visual Space Perception.

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  • 1. Visual Space Perception Wednesday, 4 June 14
  • 2. 1.The Problem ofVisual Space Perception Wednesday, 4 June 14
  • 3. The Physical World and the Perceptual World Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 10. Geometrical Relationships Wednesday, 4 June 14
  • 11. Geometrical Relationships • Physical Space Wednesday, 4 June 14
  • 12. Geometrical Relationships • Physical Space • Object can be displaced / rotated without deformation Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 19. Wednesday, 4 June 14
  • 20. • Relationships among Spaces - Perceived and Physical Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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. Wednesday, 4 June 14
  • 27. Wednesday, 4 June 14
  • 28. • Distal objects and scenes can be observed directly Wednesday, 4 June 14
  • 29. • Distal objects and scenes can be observed directly • Perception cannot be observed directly Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 35. Distal - Proximal Relationships Wednesday, 4 June 14
  • 36. Distal - Proximal Relationships • Projective Geometry: Geometrical Optics Wednesday, 4 June 14
  • 37. Distal - Proximal Relationships • Projective Geometry: Geometrical Optics • The light falling on an eye can come Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 42. Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 50. Wednesday, 4 June 14
  • 51. • Proximal Geometry - Geometry of Perspective Wednesday, 4 June 14
  • 52. • Proximal Geometry - Geometry of Perspective Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 57. “The Problem ofVisual Space Perception” Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 62. 2. Spatial Localization :Visual Directions Wednesday, 4 June 14
  • 63. Visual Directions Wednesday, 4 June 14
  • 64. Visual Directions • Visual directions experienced when viewing a scene with two eyes Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 67. Monocular Localization of Directions Wednesday, 4 June 14
  • 68. Monocular Localization of Directions • MonocularVisual Field Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 73. Wednesday, 4 June 14
  • 74. • BinocularVisual Field Wednesday, 4 June 14
  • 75. • BinocularVisual Field • Superimposed monocular fields of two eyes Wednesday, 4 June 14
  • 76. • BinocularVisual Field • Superimposed monocular fields of two eyes • Max width = ~200º with 120º of binocular field Wednesday, 4 June 14
  • 77. Wednesday, 4 June 14
  • 78. • Objective Directions:Visual Lines Wednesday, 4 June 14
  • 79. • Objective Directions:Visual Lines • Visual Line - locus of distal points that stimulate a given point on the retina of a single eye Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 82. • Relationship between distal points and their representation in the proximal stimulus for a single eye Wednesday, 4 June 14
  • 83. Wednesday, 4 June 14
  • 84. • Subjective Directions: Visual directions Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 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). Wednesday, 4 June 14
  • 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 Wednesday, 4 June 14
  • 89. Wednesday, 4 June 14
  • 90. • Vergence Movements Wednesday, 4 June 14
  • 91. • Vergence Movements • Conjunctive eye movements that maintain a constant convergence angle Wednesday, 4 June 14
  • 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. Wednesday, 4 June 14
  • 93. • tan y/2 = A / 2D • ~ y = A/D for small y in radians Wednesday, 4 June 14
  • 94. Binocular Localizarion Wednesday, 4 June 14
  • 95. Binocular Localizarion • Well’s Experiments Wednesday, 4 June 14
  • 96. Binocular Localizarion • Well’s Experiments • Fusion Wednesday, 4 June 14
  • 97. Binocular Localizarion • Well’s Experiments • Fusion • Horopter andVieth-Muller Circle Wednesday, 4 June 14
  • 98. Binocular Localizarion • Well’s Experiments • Fusion • Horopter andVieth-Muller Circle • Next -- 3. Fusion and Horopters Wednesday, 4 June 14
  • 99. Wednesday, 4 June 14