Spatiotemporal Information Processing No.3 3 components of Virtual Reality-2 Display System Kazuhiko...
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Transcript of Spatiotemporal Information Processing No.3 3 components of Virtual Reality-2 Display System Kazuhiko...
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
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 )