3D stereoscopy

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3D stereoscopy
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What is Stereoscopy?

• Taking 2 Images of the same scene from different
  viewpoints
• Viewpoints approximate human eyesight
• Recombining views in different ways mimics how we
  would see the scene

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Origins

• Almost as early as photography first example
  publicly shown at the London World Exhibition in
  1851
• Two independent images shown side by side
• Stereoscopes were used to direct each eye to only
  one image each. The concept was a novelty without
  modern film techniques or overlays.

Stereoscope circa 1861, uses double image of
stationary shot
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Basics

• Optical focus in Stereoscopics relies on the
  converging of both images at a point in space or
  object of interest
• Surroundings at different depths appear blurred
  based on Image Parallax

• This occurs based on size differences of
  peripheral objects from fish-eye effect

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Human Acceptance

• Our acceptance of the images shown are affected
  by differences between
• Distance of viewer to screen and screen size, and
  the cameras convergence point and field of view.
• Our expected object of focus (when darting our
  eyes around to follow action) and often
  stationary convergence of images.
• These issues can make some people more or less
  able to grasp a 3D effect
• On the flip side, most peoples brains will fill
  in the details naturally, allowing for infinite
  convergence

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Anagraph Technique

• Filters left and right images through red and
  cyan lenses, and overlays on screen
• Red(left) frame seen only via right eye, and vice
  versa
• Process tricks brain into accepting final image
  as 3D, though possible to create with single
  image
• Full color not usually possible red-green
  (yellow)and red-blue (magenta) often hinder the
  effect, when unintentionally filtered.

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Shutter Technique

• Modern approach, like those sold by Nvidia today,
  and used in industry.
• Left and right views alternated frame-by frame
• This produced ghosting effect at low refresh
  rates (where mentally, a sense of flickering is
  present)
• Requires special Shutter glasses and
  compatible monitor and video cards

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Shutter Glasses

• Infrared-receiving glasses with liquid-crystal
  overlays over lenses
• LC overlay similar to calculator symbols apply
  voltage to darken one eye at a time. Otherwise,
  transparent
• Synched with refresh rate of monitor via IR
  emitting hardware component

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LCD monitor advancements

• LCD Monitors have only recently gained fast
  enough refresh rates to allow for 3D viewing
• smearing effect of early LCDs caused by slow
  transition time of pixels the time it takes for
  a pixel to light up and return to darkness. Fast
  on-screen movement demonstrates this effect.
• 120Hz refresh rate 8.33ms transition rate

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Nvidia GeForce 3D

• A few monitors and a variety of Geforce cards
  currently supported.
• With the right drivers, any DirectX-compatible 3D
  applications are supported, and graphic cards are
  limited more by GPU speed then custom hardware
  requirements.
• List of games available, includes most titles
  produced in the last few years.
  (http//www.nvidia.com/object/GeForce_3D_Vision_3D
  _Games.html)

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Market Adoption

• Due to advancements, a modern video card(300),
  shutter glasses(100) and compatible monitor (650)
  can cost a modest 1000 US
• High-end games must cut framerate or resolution
  in half for 3D.
• Glasses are dark even when clear, similar to
  viewing through sunglasses.
• Segment of population does not see effect

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Links

• http//www.stereoscopy.com/faq/digitalprojection-b
  eginners-guide.html
• http//www.nvidia.com/object/geforce_3D_vision_CD_
  1.06.html
• http//www.stereo.canonia.pl/index-en.html
• http//www.stereo3d.com/formats.htm
• http//cmst.curtin.edu.au/publicat/1993-01.pdf