Multimedia SystemsMultimedia Systems
3D Technologies3D Technologies
Course PresentationCourse Presentation
Mahdi Amiri
May 2014
Sharif University of Technology
Binocular Vision (Two Eyes)AdvantagesAdvantages
A spare eye in case one is damaged.
A wider field of view (FOV).
Maximum horizontal FOV of humans: ~200º (with
two eyes)
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two eyes)
One binocular FOV (seen by both eyes): ~120º
Two uniocular FOV (seen by only one eye): ~40º
Binocular summation: The ability to detect faint
objects is enhanced (neural summation).
Perception of depth.
Depth PerceptionCyclopean ImageCyclopean Image
Cyclopean image is a single mental image of a scene
created by the brain by combining two images received
from the two eyes.
The mythical Cyclops The mythical Cyclops
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The mythical Cyclops The mythical Cyclops
with a single eyewith a single eye
Depth PerceptionCues (Cont.)Cues (Cont.)
Accommodation of the eyeball (eyeball focus)
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Interposition
Occlusion of one object by another
Focus by changing the curvature of the lens.Focus by changing the curvature of the lens.
OcclusionOcclusion
Depth PerceptionCues (Cont.)Cues (Cont.)
Linear perspective (convergence of parallel edges)
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Parallel lines such as railway lines Parallel lines such as railway lines
converge with increasing distance.converge with increasing distance.
Depth PerceptionCues (Cont.)Cues (Cont.)
Familiar size and Relative size
subtended visual angle of an object of known size
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A retinal image of a small car is also A retinal image of a small car is also
interpreted as a distant car.interpreted as a distant car.
Depth PerceptionCues (Cont.)Cues (Cont.)
Aerial Perspective
Vertical position (objects higher in the scene
generally tend to be perceived as further away)
Haze, desaturation, and a shift to bluishness
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Haze, desaturation, and a shift to bluishness
Shift to bluishnessShift to bluishness HazeHazeHightHight
Depth PerceptionCues (Cont.)Cues (Cont.)
Light and Shade
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ShadowShadow
Depth PerceptionCues (Cont.)Cues (Cont.)
Change in size of textured pattern detail.
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Depth PerceptionCues (Cont.)Cues (Cont.)
Motion parallax
When an observer moves, the apparent relative motion of
several stationary objects against a background gives hints about
their relative distance.
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This effect can be seen clearly when driving in a This effect can be seen clearly when driving in a
car. Nearby things pass quickly, while far off car. Nearby things pass quickly, while far off
objects appear stationary.objects appear stationary.
Depth Perception
A person’s eye are about 65mm apart A person’s eye are about 65mm apart
from each other. The two eyes converge from each other. The two eyes converge
on the object of attention.on the object of attention.
We see a single, Cyclopean, We see a single, Cyclopean,
image from the two eyes' images.image from the two eyes' images.
Cues: Cues: StereopsisStereopsis
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The cube is shifted to the right in left The cube is shifted to the right in left
eye's image.eye's image.
The cube is shifted to the left in the The cube is shifted to the left in the
right eye's image.right eye's image.
The brain gives each point in the Cyclopean The brain gives each point in the Cyclopean
image a depth value, represented here by a image a depth value, represented here by a
grayscale grayscale depth mapdepth map..
Depth PerceptionCues, SummaryCues, Summary
Monocular Cues (involve those cues that exist for a
single eye)Accommodation of the eyeball
Interposition (Occlusion)
Linear perspective
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Linear perspective
Familiar size and Relative size
Aerial Perspective
Light and Shade
Change in size of textured pattern
Monocular Movement Parallax
Binocular Cues (Cues that involve both eyes)
Stereopsis
3D TechnologiesTypes of 3D DisplaysTypes of 3D Displays
Stereoscopic
Provides a different image to the viewer's left and
right eyes (generally user has to use special spectacles).
Autostereoscopic
Uses optical components in the display, rather than worn
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Uses optical components in the display, rather than worn
by the user, to enable each eye to see a different image.
Computer-Generated Holography (CGH)
Create a light field identical to that which would
emanate from the original scene.
Volumetric displaysDisplay points of light within a volume. Such displays
use voxels instead of pixels.
StereoscopyDefinitionDefinition
Presenting two offset images separately to the left and
right eye of the viewer.
Three strategies:
Have the viewer wear eyeglasses to combine
separate images from two offset sources.
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separate images from two offset sources.
Have the viewer wear eyeglasses to filter offset
images from a single source separated to each eye.
Have the light source split the images directionally
into the viewer's eyes (no glasses required
, Autostereoscopy).
StereoscopyTwo Offset SourcesTwo Offset Sources
Stereoscope
A stereoscope is composed of two pictures mounted next to each other, and a set of lenses to view the pictures
through. Each picture is taken from a slightly different viewpoint that corresponds closely to the spacing of
the eyes. The left picture represents what the left eye would see, and likewise for the right picture. When
observing the pictures through a special viewer, the pair of two-dimensional pictures merge together into a
single three-dimensional photograph. First invented by Sir Charles Wheatstone in 1838.
Charles WheatstoneCharles Wheatstone
18021802--18751875
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StereoscopyTwo Offset SourcesTwo Offset Sources
Viewers
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Conway Stereo ViewerConway Stereo Viewer
1920s1920s--30s Stereo Viewer30s Stereo Viewer
HeadHead--Mounted Display (HMD)Mounted Display (HMD)
An HMD with a separate video source displayed in front An HMD with a separate video source displayed in front
of each eye to achieve a stereoscopic effect.of each eye to achieve a stereoscopic effect.
StereoscopyFiltering Single SourceFiltering Single Source
Autostereogram
Anaglyph image
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Polarization of light
Linearly polarized
Circularly polarized
A linear polarizer converts an A linear polarizer converts an unpolarizedunpolarized beam into beam into
one with a single linear polarization. The vertical one with a single linear polarization. The vertical
components of all waves are transmitted, while the components of all waves are transmitted, while the
horizontal components are absorbed and reflected.horizontal components are absorbed and reflected.
Anaglyph (3D photograph) of a Anaglyph (3D photograph) of a
column head in Persepolis, Iran.column head in Persepolis, Iran.
AutostereogramStereogramStereogram
3D craze of the 90’s
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Autostereogram
Decoupling focus from Decoupling focus from
convergence tricks the brain into convergence tricks the brain into
seeing 3D images in a 2D seeing 3D images in a 2D
autostereogramautostereogram..
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AutostereogramStereogramStereogram
3D craze of the 90’s
www.magiceye.comwww.magiceye.com
Multimedia Systems, Mahdi Amiri, 3D TechnologiesPage 19Multimedia Systems, Spring 2011, Mahdi Amiri, 3D Technologies
AutostereogramStereogramStereogram
3D craze of the 90’s
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www.magiceye.comwww.magiceye.com
AutostereogramViewing InstructionsViewing Instructions
Magic Eye images may be easier to see if viewed on paper rather than a
computer screen. If possible, print this image and follow the instructions
below. (You don't need to print in color.)
Hold the center of the printed image right up to your nose. It should be
blurry. Focus as though you are looking through the image into the distance.
Very slowly move the image away from your face until the two squares above
The hidden imageThe hidden image
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Very slowly move the image away from your face until the two squares above
the image turn into three squares. If you see four squares, move the image
farther away from your face until you see three squares. If you see one or two
squares, start over!
When you clearly see three squares, hold the page still, and the hidden
image will magically appear. Once you perceive the hidden image and depth,
you can look around the entire 3D image. The longer you look, the clearer the
illusion becomes. The farther away you hold the page, the deeper it becomes.
Good Luck!
AutostereogramRandom Dot AutostereogramRandom Dot Autostereogram
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The hidden imageThe hidden image
AutostereogramRandom Dot AutostereogramRandom Dot Autostereogram
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AutostereogramStereogramStereogram
Random dot stereogram was invented by Dr. Bela Julesz in 1959.
Fig. 1. By using uniform, Fig. 1. By using uniform,
randomly distributed dots, randomly distributed dots,
Dr. Dr. JuleszJulesz eliminated the eliminated the
depth cues that are inherent depth cues that are inherent
in recognizable images.in recognizable images.
Dr. Dr. BelaBela JuleszJulesz
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in recognizable images.in recognizable images.
Fig. 3. Create a new rectangle Fig. 3. Create a new rectangle
identical to the original rectangle, identical to the original rectangle,
except that the dots within the small except that the dots within the small
shape have been shifted to the left.shape have been shifted to the left.
Fig. 2. Within the rectangle Fig. 2. Within the rectangle
select a group of dots that make select a group of dots that make
up a small shape (here a circle).up a small shape (here a circle).
Fig. 4. When the two Fig. 4. When the two
rectangles (Fig. 1 and Fig. 3) rectangles (Fig. 1 and Fig. 3)
are viewed together as a are viewed together as a
stereo pair, the image of the stereo pair, the image of the
circle appears to float above circle appears to float above
the background.the background.
AutostereogramBirth of AutostereogramBirth of Autostereogram
In 1979, Christopher Tyler, a student of Dr. Julesz, assisted by computer programmer
Maureen Clarke, discovered that the offset scheme could be applied to a single image.
Christopher TylerChristopher Tyler
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The hidden imageThe hidden image
Anaglyph ImageConceptConcept
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The anaglyph method produces two slightly offset images, each The anaglyph method produces two slightly offset images, each
individually tinted in either red or cyan. The redindividually tinted in either red or cyan. The red--cyan glasses then cyan glasses then
filter the light appropriately, meaning individual eyes only see the filter the light appropriately, meaning individual eyes only see the
image meant for them. The brain then merges the two slightly image meant for them. The brain then merges the two slightly
different images to produce the 3D effect. This is the main process different images to produce the 3D effect. This is the main process
currently being used on 3D currently being used on 3D BluBlu--Ray releases and on TV broadcasts.Ray releases and on TV broadcasts.
RedRed--blue glassesblue glasses
RedRed--cyan glassescyan glasses
cyan = green + bluecyan = green + blue
Anaglyph ImageConceptConcept
How to create
www.decotechsoftware.com/sim/manual/pages/others/basic_concepts_of_stereo_img.htmlwww.decotechsoftware.com/sim/manual/pages/others/basic_concepts_of_stereo_img.html
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Anaglyph ImageComputer ProcessComputer Process
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3D TechnologiesThat’s not all.That’s not all.
To be continued…
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Polarization of LightConceptConcept
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The The polarisedpolarised method is one which is method is one which is becommingbecomming the the
method of choice when displaying 3D images. Two method of choice when displaying 3D images. Two
images are projected at right angles to each other which images are projected at right angles to each other which
are then filtered by the are then filtered by the polarisingpolarising glasses, again meaning glasses, again meaning
each individual eye only sees the image intended for it, each individual eye only sees the image intended for it,
much in the same was as the anaglyph method.much in the same was as the anaglyph method.
Linear Polarized 3D GlassesLinear Polarized 3D Glasses
Polarization of LightThe Common Types of The Common Types of PolarizersPolarizers
Linear
Eyeglass contain a pair of
orthogonal polarizing filters
Low-cost eyeglasses
If viewers tilt their heads ���� Corrupts
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If viewers tilt their heads ���� Corrupts
Circular
The most widely used technology
for watching 3-D films in theatres
RightRight--handed/Clockwise circularly polarized light displayed handed/Clockwise circularly polarized light displayed
with and without the use of components. This would be with and without the use of components. This would be
considered Leftconsidered Left--handed/Counterhanded/Counter--Clockwise circularly Clockwise circularly
polarized if defined from the point of view of the source.polarized if defined from the point of view of the source.
Polarization of LightCircular PolarizationCircular Polarization
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A rightA right--handed/clockwise circularly handed/clockwise circularly
polarized wave as defined from the polarized wave as defined from the
point of view of the source.point of view of the source.
A LeftA Left--handed/counterhanded/counter--clockwise clockwise
circularly polarized wave as defined circularly polarized wave as defined
from the point of view of the source.from the point of view of the source.
RealDRealD glassesglasses
3D TechnologiesAutostereoscopicAutostereoscopic
Concept
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Example of parallax barrier. Each eye sees Example of parallax barrier. Each eye sees
different pixels of the image.different pixels of the image.
Comparison of parallaxComparison of parallax--barrier and barrier and lenticularlenticular
autostereoscopicautostereoscopic displays. Note: The figure is displays. Note: The figure is
not to scale.not to scale.
3D TechnologiesAutostereoscopicAutostereoscopic
Example devices
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The Nintendo 3DS uses parallax The Nintendo 3DS uses parallax
barrier barrier autostereoscopyautostereoscopy to to
display a 3D image.display a 3D image.
3D TechnologiesHolographyHolography
Invented in 1947 by Dennis Gabor.
Holography is a technique that allows the light
scattered from an object to be recorded and later
reconstructed so that when an imaging system (a
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reconstructed so that when an imaging system (a
camera or an eye) is placed in the reconstructed
beam, an image of the object will be seen even
when the object is no longer present.
Dennis Gabor, 1900Dennis Gabor, 1900--19791979
HolographyConceptConcept
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Holographic recording processHolographic recording process
Holographic reconstruction Holographic reconstruction
processprocess
HolographyABCABC
ABC
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Holographic recording processHolographic recording process
WorkspaceWorkspace
HolographyInterferenceInterference
ABC
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InterferenceInterference
HolographyDiffractionDiffraction
Diffraction example
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DiffractionDiffraction
Volumetric DisplayVoxelsVoxels (3D Pixels)(3D Pixels)
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A series of voxels in a stack with
a single voxel highlighted.
Volumetric DisplayVoxelsVoxels (Different resolution)(Different resolution)
www.bilderzucht.de/blog/3d-pixel-voxel/
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Different resolutions
Filled with Color
Volumetric DisplayVoxelsVoxels (Different edges)(Different edges)
www.bilderzucht.de/blog/3d-pixel-voxel/
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Volumetric DisplayVoxelsVoxels (Different materials)(Different materials)
www.bilderzucht.de/blog/3d-pixel-voxel/
Different Materials on accordant
positions of the car
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3D TechnologiesLiquid Crystal (LC) Shutter GlassesLiquid Crystal (LC) Shutter Glasses
Pros
Mostly eliminate "ghosting" which is a problem with other 3D
display technologies such as RealD 3D
Unlike red/cyan color filter 3D glasses, LC shutter glasses are
color neutral enabling 3D viewing in the full color spectrum.
A pair of A pair of CrystalEyesCrystalEyes
shutter glassesshutter glasses
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color neutral enabling 3D viewing in the full color spectrum.
Cons
Flicker can be noticeable except at very high refresh rates, as each eye
is effectively receiving only half of the monitor's actual refresh rate.
LC shutter glasses are shutting out light half of the time ... darker
picture perceived by the viewer.
Expensive glasses (Over $100)
Shutter glasses are also matched to the TV so it may not be possible to
use your shutter glasses with a different brand 3DTV.