Lec16, 3D Technologies, v1.01.ppt - Sharifce.sharif.edu/courses/92-93/2/ce342-1/resources/root/Lectures/Lec16... · 3D Technologies Course Presentation Mahdi Amiri May 2014 Sharif

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)

Multimedia Systems, Mahdi Amiri, 3D TechnologiesPage 1

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


The mythical Cyclops The mythical Cyclops

with a single eyewith a single eye

Depth PerceptionCues (Cont.)Cues (Cont.)

Accommodation of the eyeball (eyeball focus)


Interposition

Occlusion of one object by another

Focus by changing the curvature of the lens.Focus by changing the curvature of the lens.

OcclusionOcclusion


Linear perspective (convergence of parallel edges)


Parallel lines such as railway lines Parallel lines such as railway lines

converge with increasing distance.converge with increasing distance.


Familiar size and Relative size

subtended visual angle of an object of known size


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.


Aerial Perspective

Vertical position (objects higher in the scene

generally tend to be perceived as further away)

Haze, desaturation, and a shift to bluishness


Haze, desaturation, and a shift to bluishness

Shift to bluishnessShift to bluishness HazeHazeHightHight


Light and Shade


ShadowShadow


Change in size of textured pattern detail.



Motion parallax

When an observer moves, the apparent relative motion of

several stationary objects against a background gives hints about

their relative distance.


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


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


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


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.


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


StereoscopyTwo Offset SourcesTwo Offset Sources

Viewers


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


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


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..




www.magiceye.comwww.magiceye.com

Multimedia Systems, Mahdi Amiri, 3D TechnologiesPage 19Multimedia Systems, Spring 2011, Mahdi Amiri, 3D Technologies




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


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



AutostereogramRandom Dot AutostereogramRandom Dot Autostereogram



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


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



Anaglyph ImageConceptConcept


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


Anaglyph ImageExampleExample

3D Box


Anaglyph ImageComputer ProcessComputer Process


3D TechnologiesThat’s not all.That’s not all.

To be continued…


Polarization of LightConceptConcept


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


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


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


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


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


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


Holographic recording processHolographic recording process

Holographic reconstruction Holographic reconstruction

processprocess

HolographyABCABC

ABC


Holographic recording processHolographic recording process

WorkspaceWorkspace

HolographyInterferenceInterference

ABC


InterferenceInterference

HolographyDiffractionDiffraction

Diffraction example


DiffractionDiffraction

Volumetric DisplayVoxelsVoxels (3D Pixels)(3D Pixels)


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/


Different resolutions

Filled with Color

Volumetric DisplayVoxelsVoxels (Different edges)(Different edges)



Volumetric DisplayVoxelsVoxels (Different materials)(Different materials)


Different Materials on accordant

positions of the car


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


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.

3D TechnologiesABCABC

Ghosting


Thank You

Multimedia SystemsMultimedia Systems

3D Technologies3D Technologies

Page 47

Thank You

1. http://ce.sharif.edu/~m_amiri/

2. http://www.dml.ir/

FIND OUT MORE AT...

Documents

Lec16, 3D Technologies, v1.01.ppt - Sharifce.sharif.edu/courses/92-93/2/ce342-1/resources/root/Lectures/Lec16... · 3D Technologies Course Presentation Mahdi Amiri May 2014 Sharif