Stereoscopic Images

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Stereoscopic Images

• Binocular vision enables us to measure depth
  using eye convergence and stereoscopic vision.
• Eye convergence is a measure of the angle between
  the eyes optical axes when fixating upon some
  point.
• Stereopsis describes the process of obtaining two
  distinct views of an object when viewed with two
  eyes.

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• Stereoscopic vision describes the three
  dimensional sensation of depth associated when
  seeing with two eyes.

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Optical Angle

• Optical Angle (eye convergence) The optical
  angle T1 of object 1 is larger than the optical
  angle T2 of object 2. So that we sense object 2
  is closer.
• The distance is measure using optical angle.

Left eye
Right eye
Object 2
Object 1
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Visual Angle

• Visual Angle The visual angle is the angle a
  viewed object subtends at the eye
• The size of object is justified based on visual
  angle. The visual angle T1 of object 1 is smaller
  than the visual angle T2 of object 2. So that we
  sense object 1 is smaller.

Object 2
Object 1
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Parallax

• Parallax is a displacement or difference in the
  apparent position of an object viewed along two
  different lines of sight .

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• This animation is an example of parallax. As the
  viewpoint moves side to side, the objects in the
  distance appear to move more slowly than the
  objects close to the camera.

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Parallax vs. Disparity

• Binocular Retinal Disparity describes the
  position shift of an object between two views.
• Parallax and Disparity are actually the same
  terms. Parallax is generally used for screen
  display while disparity is used for retinal.
• Stereo vision is created based on the principal
  of parallax.

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How to make stereo images?

• The distance between two pupils of the eyes is
  around 6.3cm7.0cm.
• You need to take pictures twice by shifting a
  disparity.
• Disparity
• 3D object distance 50

object
right
left
disparity
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• Examples

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Shutter Glasses  

• Interlacing
• Page-Flipping

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Interlacing
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Page-Flipping

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Perspective Projection
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Stereo perspective projection (3.5)

• The left and right eyes are separated by Se

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• To compute the perspective projection of the box
  such that the left eye is gazing along the
  z-axiz, the x-coordinates are translated by Se/2

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• To compute the perspective projection of the box
  such that the right eye is gazing along the
  z-axiz, the x-coordinates are translated by Se/2

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example
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x y z xpl ypl xpr ypr
5 5 40 0.58 1.67 2.75 1.67
5 -5 40 0.58 -1.67 2.75 -1.67
-5 5 40 -2.75 1.67 -0.58 1.67
-5 -5 40 -2.75 -1.67 -0.58 -1.67
5 5 50 0.5 1.43 2.36 1.43
5 -5 50 0.5 -1.43 2.36 -1.43
-5 5 50 -2.36 1.43 -0.5 1.43
-5 -5 50 -2.36 -1.43 -0.5 -1.43