copyright@jung,bily,jingjing 20/10/2004 display technology: stereo&3d display technologies david...

20/10/2004 copyright@Jung,Bily,Jingjing

Display Technology:

Stereo&3D Display Technologies

David F. McAllister

Department of Computer Science

North Carolina State University

Raleigh, NC 27695-8206

Tel:919-233-8164

Fax:919-233-8578

Email: [email protected]


Recently there have been rapid advancements in

3D techniques and technologies.

Old techniques have been improved, and new ones have been developed.

Our brain integrates these two images into one three-dimensional

picture.


OverviewOverview

IntroductionDepth Cues Physiological Depth Cues

Psychological Depth Cues

A Technology TaxonomyStereo Pairs

Display Technology OverviewSeparating Left and Right Eye ViewsCross Talk

Field Sequential TechniquesTime-Parallel Techniques


Accommodation (short viewing distances)

Process of lens changing shape

Convergence (short viewing distances)

Inward rotation of eyes

Binocular disparity (medium viewing distances)

Difference in the images projected on the left and right eye retinas

Motion parallaxDifferent view of a scene in response to movement

Physiological depth Physiological depth cuescues

<Depth cues>

< Taxonomy >

< Stereo Pairs >

Psychological depth cues


http://info.geography.siu.edu/people/oyana/Teaching/485_551/5th_lecture.htm

single-image random dot stereograms created by Peter Chang and Gareth Richards in England


Linear perspective Shading and shadowing

Physiological depth cues

<Depth cues>

< Taxonomy >

< Stereo Pairs >

Psychological depth Psychological depth cuescues


Aerial perspective Interposition


<Depth cues>

< Taxonomy >

< Stereo Pairs >



Retinal image size Texture gradient

Color


<Depth cues>

< Taxonomy >

< Stereo Pairs >



Stereo pairHolographic

Multiplanar (Volumetric)


<Depth cues>

< Taxonomy < Taxonomy >>




<Depth cues>

Stereo Stereo PairsPairs


< Taxonomy >


Stereo Pairs

Horizontal disparity

Left Image+ Right Image=Spatial ImagesTwo interleaved images unite as one.


Vertical disparity

Correct

Incorrect


<Depth cues>

< Taxonomy >

< Stereo < Stereo Pairs >Pairs >



• Cross talk is when left images reach right eye, and right images reach left eye

IntroductionDepth Cues Physiological Depth Cues

Psychological Depth Cues

A Technology TaxonomyStereo Pairs

Display Technology OverviewSeparating Left and Right Eye ViewsCross Talk



<Display Technologies Overview>

• Images are presented alternately

• Most common techniques is shutter glass stereo

• Takes advantage of persistence of vision

• Frame rate must be very high



• Both views are presented simultaneously

• Dual viewing:• Anaglyph (red/green) glasses• Polarised glasses• Main issue is cross—talk

• Separate viewing:• Head--mounted displays

<Display Technologies Overview>

Time-Parallel Techniques

Field Sequential Techniques


OverviewOverview

3D Displays:Viewing Devices Required Field Sequential Devices

CrystalEyes ZScreen system

Pulfrich Technique FakeSpace PUSH Display

Work Bench Displays VREX Micropolarizers Large Format Displays

IMAX Fakespace Systems Displays

The VisionDome


• Glasses:• LCD ‘shutter’ or active stereo (most systems)---e.g. CrystalEyes• LCD display technology• Two crossed,polarized layers per eye• One permanently polarized• One switchable• Controlled by an IR signal

• Cross polarized or ‘passive’ stereo (e.g. IMAX / ZSreen glasses)• two lenses• Polarized in orthogonal directions• Two projectors produce different images --Polarize with filters


• What is a CrystalEyes like?• What is it? One kind of stereo shutter glasses,using active glass system

• How does it work?• Creates illusion of stereo by alternating left and right eye iimages between frames• Glasses alternately block out each eye so that each eye sees every other image• Requires very high refresh rates• Currently used for many systems including CAVE

• Property merit • A high dynamic range----ensure that only the correct image is shown to each eye. Not suffer from ghosting and double-images result Disadvantages• Display system must have a very high frame rate• Glasses must have some power supply so batteries

or wires are required

CrystalEyesField Sequential Devices

Pulfrich Technique

FakeSpace PUSH Display

ZScreen system

Work Bench Displays

VREX Micropolarizers



<Depth cues>

Pulfrich Technique

FakeSpace PUSH Display

ZScreen system• What is it?• Passive glass system• Polarized glasses

• How does it work

• Property Advantages:• don’t need as quick of a refresh rate as you do with shutter glasses• cheap an require no power supply Disavantages:• low dynamic range, may suffer from ghosting or image cross talk.

• Solution to prevent ghosting• electrode-segmentation------increasing the effective dynamic range of the system and produces a high quality stereo image

Work Bench Displays



Ploarized glasses

• Cheap

• Light and comfortable

• More or less indestructible

• Continuous image in both eyes

(2 projectors)

• Two projectors---alignment issues

• Non-polarizing screen required

• 50% light loss

• Can’t tilt your head more than a few

Degrees

Shutters vs polarization

• Expensive( ~$250+)

• One display(Screen or projector)

• Heavier and more uncomfortable

--Batteries and electronics inside

• Batteries run out – maintenance

issues

• Much more fragile

• 50% light loss

---could avoid with two active layers


CrystalEyes

Field Sequential Devices

Pulfrich Technique

ZScreen system

• Pulfrich Effect• This effect is called Pulfrich-effect in honor of the german

physicist Carl Pulfrich (1858-1927).• When viewing a moving image,the user can see two different images if a filter is placed over one eye• Usually a neutral-density filter• Also works with sunglasses with one lens removed• The perception in the covered eye is slowed,thus that eye sees an older image• If the images are created correctly(for example,rotating the

scene about a vertical axis),the current image and the delayed image will form a stereo pair

• Cheap and capable of being broadcast,but requires constant motion

Fakespace push displayWork Bench

Displays


•Pulfrich-Glasses

The darkened eye reacts slower to optical stimuli. It's based on a time-parallax in horizontally moving objects. The parallax is determined by the speed of movement. In case the movement stops the image turns 2D.


Fakespace push display Work Bench

Displays


Pulfrich Technique

CrystalEyes


ZScreen system

• How does it work?• using a box shaped binocular viewing device

with attached handles which is mounted on a triad of cylindrical sensors.


• ‘Workbench’• Similar to a wall display• Tiltable• Possibly can be made flat• Usually used with tracking• Usually used by one person• Used as a wide screen monitor• Using active glasses stereo technique• User has very little room to move around• Field of regard is small

Fakespace push displa

y Work Bench Displays


Pulfrich Technique

CrystalEyes ZScreen system


Fakespace ImmersaDesk R2

Fakespace ImmersaDes M1

FakeSpace ImmersaDesk

A “portable” semi-immersive environment:

VR ‘Responsive’Workbench


• What is it?• an optical device that can change the po

larization of an LCD display on a line by line basis.

• How does it work• A periodic array of microscopically small

polarizers that spatially alternate between mutually perpendicular polarizing states.

• Passive polarized glasses are needed to view the image

• Requiring a single-frame stereoscopic image format combining a left-eye perspective view with a right-eye perspective view to form as composite image,which contains both left and right-eye information alternating on a line-by-line basis.


Pulfrich Technique

CrystalEyes


ZScreen system

Fakespace push display

Work Bench Displays


<Large Format Displays>

IMAX

Fakespace Systems Displays

The Vision Dome

• How does it workHow does it work when projecting stereo,IMAX uses the when projecting stereo,IMAX uses the standard field sequential polarized projectistandard field sequential polarized projection mechanism where the user wears passion mechanism where the user wears passive glasses.ve glasses.

• allow multiple users allow multiple users IMAX SCREEN

IMAX PROJECTOR


<Large Format Displays> IMAX

Fakespace Systems

Displays The Vision Dome

• One kind of immersive technology

• 4-sided Cave

• UCL’s Cave• 4-sided CAVE in UNIMAS VR Lab, Kota

Samarahan, Sarawak


• a Extension of flat screen stereo—Cave• Small room theatre• Back-projected screens: walls,Floor,Ceiling required active shuttering glasses• Any combination from 2-6 sides of box• Designed to avoid HMD(Head Mouted Device) limitations on update rate


• When the idea of a CAVE was conceived,it was originally supposed to be 6-sided. • 6-sided CAVE

– 2.5m x 2.5m x 2.5m

– Back projektion

– Aktive stereo

– 1 person with tracking,+ a few observers without tracking

IMAX

The Vision Dome

IMAX

Fakespace Systems

Displays



• A another Extension of flat screen

stereo—GeoWall

• The GeoWall created to be a cheap

and portable alternative to the CAVE

• Uses two projectors and polarized light

• glasses (passive glasses system)

• Can be used for an entire classroom full

of people


The Vision Dome



The Vision Dome


• What is it? Multiple projector system Project onto domed surface overhe-ad Can cover as much as 180 or more 180*180 ---Hayden Planetarium(Trimension) Using distorted images:


IMAX


The Vision Dome

• How the environments looks in it?

Distorted images


Alternating PairsMoving Slit Parallax

BarrierThe DTI SystemSeaphone DisplayThe Sanyo DisplayThe HinesLab Display

Oscillating Plane MirrorVarifocal MirrorRotating Mirror

Autostreoscopic DisplaysAutostreoscopic Displays

Volumetric DisplaysVolumetric Displays

OverviewOverview


Alternating PairsAlternating Pairs

Moving Slit Parallax Barrier

The DTI System

Seaphone Display

The Sanyo Display

The HinesLab Display

Alternating Pairs

Oscillating Plane Mirror

Varifocal Mirror

Rotating Mirror


Figure 1VISIDEP


Moving Slit Parallax Moving Slit Parallax BarrierBarrier


The DTI System

Seaphone Display

The Sanyo Display


Alternating Pairs


Varifocal Mirror

Rotating Mirror

- A mechanical moving slit display

- Popularized by Homer Tilton

- Parallactiscope

- No commercially viable products



The DTI SystemThe DTI System


The DTI System

Seaphone Display

The Sanyo Display


Alternating Pairs


Varifocal Mirror

Rotating Mirror

Figure 2

- Each stereoscopic image is half the full resolution of the screen

-The stereoscopic display is quite sensitive to the position of the viewer’s head


Figure 3From above


Seaphone DisplaySeaphone Display


The DTI System

Seaphone Display

The Sanyo Display


Alternating Pairs


Varifocal Mirror

Rotating Mirror

- A right eye system, a left eye system and head tracking system

- The stereo viewing area determines the number of viewers


Figure 4


Seaphone DisplaySeaphone Display


The DTI System

Seaphone Display

The Sanyo Display


Alternating Pairs


Varifocal Mirror

Rotating Mirror


Figure 5


The Sanyo DisplayThe Sanyo Display


The DTI System

Seaphone Display

The Sanyo Display


Alternating Pairs


Varifocal Mirror

Rotating Mirror


-Use LC technology

-Head tracking System

-Use two image splitter

- No ghosting


The HinesLab DisplayThe HinesLab Display


The DTI System

Seaphone Display

The Sanyo Display


Alternating Pairs


Varifocal Mirror

Rotating Mirror


Figure 6


Oscillating Plane MirrorOscillating Plane Mirror


The DTI System

Seaphone Display

The Sanyo Display


Alternating Pairs


Varifocal Mirror

Rotating Mirror

Volumetric DisplayVolumetric Display

- No disconnection of accommodation

- All depth cues would be consistent

- According to the focal length of The mirror, dramatic improvement in view volume depth can be obtained.


Varifocal MirrorVarifocal Mirror


The DTI System

Seaphone Display

The Sanyo Display


Alternating Pairs


Varifocal Mirror

Rotating Mirror


- A commercial multiplanar

- Use a flexible circular mirror anchored at the edges.


Rotating MirrorRotating Mirror


The DTI System

Seaphone Display

The Sanyo Display


Alternating Pairs


Varifocal Mirror

Rotating Mirror


-Use RGB lasers for point plotting and a double helix mirror rotating at 600 rpm as reflecting device

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