Spatiotemporal Information Processing No.3 3 components of Virtual Reality-2 Display System Kazuhiko HAMAMOTO Dept. of Information Media Technology, School.

Spatiotemporal Information ProcessingNo.33 components of Virtual Reality-2Display System

Kazuhiko HAMAMOTO

Dept. of Information Media Technology,

School of Information and Telecommunication Eng.,

Tokai University, Japan

Today’s Contents

Perception of depth and distance The crystalline lens Binocular convergence Binocular parallax

Head Mounted Display Large sized screen

Stereoscopy for large sized screen Anaglyph Polarization method Active method

Immersive Virtual Environment 3D display for naked eyes

The relationship among 3 components (review)

Person

real space virtual space

Simulation system

Display system

Sensing system

computer

Visual Display

Role of visual display To give user visual presence 3 components of visual presence

a wide field of vision Perception of depth and distance High resolution

Discovery of the visual area in brain : 1855 Theory of 3 primary colors : 1800

Mechanism of perception of depth and distance

Less than 2m Accommodation of the crystalline lens

Less than 20m Binocular convergence

Less than 100m Binocular parallax = “stereopsis”

Less than 200m Motion parallax

Accommodation of the lens and the visual angle

Accommodation of the lens Focus adjustment of retinal image Ciliary muscle and elasticity of the lens adjust the

thickness of the lens Distance is estimated from the muscle’s tension Not so good precision and effective in 2m area

The visual angle Defined by the distance and size of an object Related to the size of retinal image Important factor as well as parallax and convergence

Eyeball

The visual angleobject

Retinal image

The lens

Mechanism of the binocular convergence

The binocular convergence Eyeballs’ motion which

want to catch an object in the central fovea

Optical angle Angle of crossing point

of the lines of sight

The distance between eye and an object is estimated from optical angle and the pupil distance

Mechanism of binocular parallax

Different perspective view in left eye and right eye caused by the pupil distance

The views are compared in visual area in brain and perception of depth is felt

The main function is to feel uneven surface of an object

Retina image

Left Right

Head Mounted Display (HMD)

Human vision : always ahead→ 　 a front view is always provided

Display in front of eye and tracker

Ultimate display VPL Inc., 　 Eyephone

Features of HMD

Advantages 3D image is available High immersive impression No need of wide area

Disadvantages Weight Resolution Design of optical lens Private use

Stereoscopy by HMD

Contradiction of depth information between optical angle and crystalline lens→ 　 not real view, like miniature model

Transform of distance to display by convex lens The display position is about 2m from eye, where the

lens doesn’t work ( called virtual plane ). No change in visual angle Only optical angle, parallax and visual angle determine

the depth.

Current status and future of HMD

Current status In the “Winter” Immersive type is mainly provided Key technologies

High resolution and small LCD Significant modification of optical system

Future Use in the field of Mixed Reality ？

CEATEC2010 NTT docomo AR walker

Large sized screen(single screen type)

Arch type screen Slope type screen

Contrivances for high immersive impression

Hemisphere typescreen

Stereoscopy for large sized screen

Use of binocular parallax anaglyph polarization method active method

Anaglyph Images are presented to

each eye in red and blue Left eye ： red filter

→only blue image reaches

Right eye ： blue filter→ only red image reaches

Lack of color information

Stereoscopy for large sized screen

鏡面反射スクリーン

Stereoscopy for large sized screen

Polarization method

Silver screen

Left image

Right image

Polarization filter

Polarization filter

Vertical

direction

Horizontaldirection

Polarization filter(horizontal)

Polarization filter(vertical)

Can see left image only

Can see right image only

Disadvantages of polarization method Screen which doesn’t change the axis of

polarization is neededSilver screen, etc. It is usually expensive than usual

2 projectors are needed

Stereoscopy for large sized screen

Linear polarization Oscillation direction of the light is constant 2 kinds of polarization filter are used, Vertical and horizontal direction. If position of head leans, cross-talk occurs. IMAX DIGITAL uses this method.

Circular polarization The light transmits circularly along traveling direction Left image and right image are separated by the circular direction. Not depend on neck angle Warner mycal uses “RealD”.

RealD=circular polarization +active

Stereoscopy for large sized screen

Active method Showing image for right eye and image for

left eye alternately by one projector. Use of special glasses with LCD shutter,

by which each of images can be presented to a corresponding eye only

TOHO CINEMAS, Kadokawa Cinema complex and 3 TV for consumer use this method

XpanD

Stereoscopy for large sized screen

One Projector

A glasses with LCD shutters

Active Shutter Method

Left image

Afterimage of right image

Right image

Active Shutter Method

Right image

Active Shutter Method

Left image

Active Shutter Method

Right image

Active Shutter Method

Left image

Active Shutter Method

Right image

Active Shutter Method

Left image

Active Shutter Method

Right image

Active Shutter Method

Features of Active method Advantage

Very few cross-talk, approximately ideal stereoscopy

Not depend on screen material disadvantage

The glass is more expensive than one for polarization method

Scene becomes dark because one side always closes.

Stereoscopy for large sized screen

Problem of current 3D - 1

3D from only “binocular parallax” Contradiction to other visual information

Information by crystalline lens and optical angle

Contradiction to other senses of organ The senses of balance and sound Former experiences

For example, 3D theatre

Taking 3D picture

Cross pointCross point

Screen position

Theatre

Seats correspond to camera position

The best seats

Distance between seat and screen depends on the seat.

6.5cm(stereo base)

Problem of current 3D - 2

Technical problem Cross-talk

The opposite eye’s image leaks out Always one side (active method)

Not natural scene presentation The brightness becomes half.

Immersive display Person is surrounded by multiple 3D screens. Only virtual space is presented to a person. Real space cannot be perceived. The display has “Tracker”. Person can be immersed in virtual space. “Simulation sickness” due to delay of change

of virtual environment to person’s motion, etc.

Stereoscopy for large sized screen

CAVE

1 user wears “tracker”. The user is called “driver”.

The binocular parallax images are presented for the driver.

Driver can see “complete” virtual space.

Display systemExample of immersive display

CABIN(5 screens CAVE at the

Univ. of Tokyo)

COSMOS(6 screens CAVE at Gifu

VR center)

TEELeX(5.5 screens CAVE at National Institute of

Multimedia Education)

Stereoscopy for CAVE

User see images projected from rear side by active method usually.

Difference from HMD, or large sized single screen The position of Virtual plane and real plane are

different. The position of Virtual plane and real plane are the

same. Width field of view without any motion User can see user own body.

HoloStage （ Tokai Univ. ）

5.46m wide×3m hight 1920×1200 ， 6600 ル lumen 10 projectors are used 4K stereo in one screen High resolution (1-2mm/pixel) Optical tracking 7.1ch ， and 3D stereo

sound system

3D LCD for naked eyes

Parallax barrier is structured by switching LC

Parallax barrier can control of the direction of the light for each of left eye and right eye

TFT LCD can present a image generated specially from left image and right image.

When ordinary 2D image is presented, parallax barrier can be turned off.

SHARP : 3D LCD （ parallax barrier method ）

Small panel for mobile, especially, game

LCD + 3D LCD switch panel + touch panel

Integration of 3D LCD switch panel and Touch panel. The increment of thickness of the panel is suppressed.

In 3D & VR exhibition 2010

3D LCD for naked eyesSHARP : 3D LCD （ parallax barrier method ）