Retinal correspondence

Retinal correspondence

1. Retinal Correspondence OPTOM FASLU MUHAMMED

2. Retinal Correspondence Retinal elements of the two eyes that share a common subjective visual direction are called corresponding retinal points

3. Cyclopean eye

4. law of sensory correspondence The existence of corresponding retinal elements with their common relative subjective visual directions is the essence of binocular vision

5. Sensory fusion The unification of visual excitations from corresponding retinal images into a single visual percept, a single visual image

6. An individual cannot see double with corresponding retinal elements. Single vision is the hallmark of retinal correspondence . Double vision is the hallmark of retinal disparity

7. For sensory fusion to occur, the images not only must be located on corresponding retinal areas but also must be sufficiently similar in size, brightness, and sharpness.

8. Unequal images are a severe sensory obstacle to fusion. Obstacles to fusion may become important factors in the etiology of strabismus. Differences in color and contours may lead to retinal rivalry

9. Motor fusion The ability to align the eyes in such a manner that sensory fusion can be maintained motor fusion is the exclusive function of the extra foveal retinal periphery

10. Retinal Rivalry When dissimilar contours are presented to corresponding retinal areas, fusion becomes impossible. Instead, retinal rivalry may be observed. This phenomenon, also termed binocular rivalry

11. Simultaneous excitation of corresponding retinal areas by dissimilar stimuli does not permit fusion; but since such excitations are localized in the same visual direction and since two objects localized in the same place give rise to conflict and confusion, one or the other is temporarily suppressed

12. Horopter Aguilonius Helmhotz

13. Physiologic diplopia On EH – single Not in EH – double

14. Fixation disparity

15. Stereopsis the relative ordering of visual objects in depth, that is, in the third dimension

16. The greater the depth effect, the greater the horizontal disparity

17. Monocular Cue Non-stereo depth cue One eye can judge its Patients with binocular vision defect  still can feel the depth perception

18. Monocular Cue Occlusion  near objects block the view of distant objects Apparent size  if two objects are actually the same size, but one appears smaller, then the small one is farther away than the larger  relative size Motion parallax and Relative velocity  near objects appear move faster than distant objects Light and Shading  distance and colour Overlapping contour *

19. Relative size

20. Motion parallax

21. Motion parallax Translocation of the head Cause the images of near objects to move opposite the head The images of far objects to move with the head Assuming the fixation point is at an intermediate distance

22. Light and shade

23. Over-lapping contours

24. Monocular cue Perspective  parallel lines converge in the distance Aerial perspective Geometric perspective Texture  becomes finer with distance Colour change  colour becomes more blue with distance  Atmospheric effect Haze  objects become fuzzy in the distance Accommodation  our brain knows how hard our eyes are working to focus

25. Aerial perspective

26. Geometric perspective

27. Refractive age

28. Depth perception Monocular cues Non stereoscopic binocular clues Stereopsis

29. Why fovea/periphery differences Range of disparities in natural scenes. Fovea - high depth acuity. Periphery - provides coarse information about where to make convergence eye movements.

30. Mistake in BSV Motoric Squint Refractive Aniseikonia Eye Sensoric Amblyopia Optical problems Visual illusion Brain Perception Experience Monocular cues Visual illusion

31. Visual illusion

32. Visual illusion

33. Visual illusion

34. Visual illusion

35. Visual illusion

36. Size illusion

37. Beuchet chair

38. Beuchet chair

39. Ames room

40. Ames room

41. Visual illusion: Shadow effect

42. Visual illusion: Shadow effect

43. Visual illusion: just 2D

44. Visual illusion: Moving texture

45. Visual illusion: Colour

46. Visual illusion: Grid illusion

47. Visual illusion: Bleeped-up

48. Visual illusion: The confuse

49. Visual illusion: Floor painting

50. Visual illusion: Single photo

51. Visual illusion: Single photo

52. Visual illusion: Bistable

53. Visual illusion: Bistable

54. Visual illusion: Bistable

55. Visual illusion: Mirage A superior mirage occurs when the air below the line of sight is colder than the air above it. A inferior mirage occurs when the air below the line of sight is hotter and has lower index bias than the air above it.

56. Mirage: hot haze Heat shimmer  refers to the inferior mirage experienced when viewing objects through a layer of heated air

57. Visual illusion: Moonbow

58. Visual illusion: Halo A sun dog (or sundog ), mock sun or phantom sun , scientific name parhelion (plural parhelia ), is an atmospheric phenomenon that creates bright spots of light in the sky, often on a luminous ring or halo on either side of the sun. Sundogs may appear as a colored patch of light to the left or right of the sun, 22° distant and at the same distance above the horizon as the sun, and in ice halos. They can be seen anywhere in the world during any season, but they are not always obvious or bright. Sundogs are best seen and are most conspicuous when the sun is low.

59. Sunset green flash The optical phenomenon known as the green flash can occur at sunrise or sunset, and it’s most often seen over low, unobstructed horizons such as the ocean.

60. Sun pillar A Sun pillar is an atmospheric phenomenon caused when high-altitude ice crystals reflect the rising or setting Sun’s reddened light.

61. Scintillation or Grid illusion

62. Visual illusion: Optic 1. Thermal Inversion The Titanic was sailing from Gulf Stream waters into the frigid Labrador Current, where the air column was cooling from the bottom up, creating a thermal inversion : layers of cold air below layers of warmer air. Extraordinarily high air pressure kept the air free of fog.

63. Visual illusion: Optic 2. Superior Mirage A thermal inversion refracts light abnormally and can create a superior mirage : Objects appear higher (and therefore nearer) than they actually are, before a false horizon. The area between the false horizon and the true one may appear as haze.

64. Visual illusion: Optic 3. Iceberg Camouflage The Californian ’s radio operator warned the Titanic of ice. But the moonless night provided little contrast, and a calm sea masked the line between the true and false horizons, camouflaging the iceberg . A Titanic lookout sounded the alarm when the berg was about a mile away—too late.

65. Visual illusion: Optic 4. Mistaken Identity Shortly before the collision, the Titanic sailed into the Californian ’s view—but it appeared too near and small to be the great ocean liner. Californian captain Stanley Lord knew the Titanic was the only other ship in the area with a radio, and so concluded this ship did not have one.

66. Visual illusion: Optic 5. Morse Lamp Lord said he repeatedly had someone signal the ship by Morse lamp “and she did not take the slightest notice of it.” The Titanic , now in trouble, signaled the Californian by Morse lamp, also to no avail. The abnormally stratified air was distorting and disrupting the signals.

67. Visual illusion: Optic 6. Distress Rockets Ignored The Titanic fired distress rockets some 600 feet into the air —but they appeared to be much lower relative to the ship. Those aboard the Californian , unsure of what they saw, ignored the signals. When the Titanic sank, at 2:20 a.m. April 15, they thought the ship might be simply sailing away.

68. Conflicting Cues: Only binocular Random Dot Stereograms

69. Conflicting Cues: Only binocular Random Dot Stereograms

70. 3D ability: 3D movie The archetypal 3D glasses, with modern red and cyan color filters, similar to the red/green and red/blue lenses used to view early anaglyph films.

71. 3D ability: 3D movie Resembling sunglasses, polarized glasses are now the standard for theatrical releases and theme park attractions.

72. 3D ability: 3D movie A pair of LCD shutter glasses used to view XpanD 3D films. The thick frames conceal the electronics and batteries

73. 3D vision ability

74. 3D vision ability

75. 3D vision ability

76. 3D vision ability

77. 3D vision ability

78. 3D vision ability

79. 3D vision ability

80. 3D vision ability

81. 3D vision ability

82. 3D vision ability

83. 3D vision ability

84. 3D vision ability

85. 3D vision ability

86. 3D vision ability

87. 3D Vision: Game

88. The hidden tiger

89. Shape of life: Pareidolia

90. Loch Ness Monster

91. Loch Ness Monster

92. Beyond the lecture I have seen with my own eyes! So now… What do you think? Seeing doesn’t mean believing Think again!

93. Thank you