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Display
Tele-Vision Mechanical - Mechanical
Photocell
Neon Tube
Photocell
1877 Proposed Mechanical Scanning
1884 Invented Circular Mechanical Scanner
1925 Mechanical TV system was achieved
1897 Cathode-ray tube (CRT) was invented
1911 Cathode-ray tube was used to display a simple image.
Tele-Vision Mechanical - Electrical
2011/1/20 Google doodle
(Kenjiro Takayanagi)
テレビ伝送実験装置の再現展示（NHK放送博物館@東京都港区愛宕山）
Tele-Vision Electrical - Electrical
Iconoscope
1927 All electrical system was
achieved.
1929 BBC starts experimental TV
broadcast.
1935 Germany starts first
periodical TV broadcast, and
was used for Berlin Olympics
Display technologies
 CRT cathode ray tube
 Only one point of fluorescent substance (
on the surface receives electrons and
emits light.
 Scanning (
) is necessary.
 Raster scan
 Pixel (
scan
) based
 Vector scan
 Draw figures
by lines.
 Do not use
pixel.
)
Display technologies
 LCD (Liquid crystal display)
 PDP (Plasma display
panel)
 Field Emission
Display
 Organic light emit
diode (OLED)
Display technologies
 Projectors
 CRT
 Digital Mirror Device
Digital Light Processing
 LCD (Three panel)  Liquid Crystal On Silicon
Mirror type LCD
B
Color Space
Put all colors in a 3D space
3 types of cone cells→3D
 CIE ( C o m m i s s i o n i n t e r n a t i o n a l e d e l ‘ é c l a i r a g e
) -RGB color space
 3 basis(
):
R(700nm), G(546.1nm), B(435.8nm)
 Additive mixtures(
)
are represented by sum of bases.
 Some colors requires negative R.
R
G
RGB color space
y
 XYZ color space
G
 Change basis from RGB to XYZ.
 XY Z is imagin ary co lo r
 Y: Lu min an ce (
)
 Avo id n e gat ive valu e s fo r all co lo rs.
 xyY color space
 Represent color by x, y. Represent Luminance by Y
𝑋
𝑌
𝑥=
,𝑦 =
𝑋+𝑌+𝑍
𝑋+𝑌+𝑍
R
 YUV color space ≈YCbCr color space ≈ Yzx
 JPEG, MPEG,TV uses this color space
B
x
CIE 1931 color space chromaticity diagram
Display and color space
 16 primary color camera
6 primary color display
RGB color display
Human perceptible
color
 6 primary color display
Display and color space

primary color TV
 Comparison of three and four
http://www.sharp.co.jp/aquos/technology/quattron/
Dynamic range of brightness
 Dynamic range of human vision: 10 8 (Starry sky - direct sunlight)
 Iris
diameter of pupil
 Sensor (Sensitivity : amount of Rhodopsin in cells)
 High Dynamic Range Display
Projector + Liquid crystal
LED + Liquid crystal
OLED (Organic Light Emitting Didode)
(
EL LED)
Visual display for virtual reality 3D space
Wide filed of view
Images change
according to eye position
Immersive(
) displays
 Head Mounted Display(HMD)
piSight 180 degree 2600x1600
Multi Projection
Oculus DK 2 960x1080 110度x90度
Gyro, accelerometer, compass
Oculus Rift 2160x1200
110degrees
HMD
 Immersive Projection Technology(IPT)
D-vision
CAVE
Immersive(
) displays
 IPT
 Rotating LED array
Multiple
projectors
 IMAX/Omnimax
Projection to wide/spherical screen
with wide angle/ fisheye lens
resolution can be problem
Twister （Tach lab.）
HMD
HMD as a magnifying glass
 Two separate images are displayed to each eye.
 Head posture is tracked by,
Mechanical Link, Gyro
Acceleration Sensor
Magnetic Sensor
etc…
 “Magnifying glass” optics is used to keep distance between eye
and image.
HMD
Camera for HMD
 Two cameras, which are at the same position as the HMD are
used.
TELESAR Tachi et al.,
http://tachilab.org/modules/projects/telesar.html
Other concerns(1) Eye distance & view angle
 Difference of eye distances generate odd size feeling
(miniature garden)
 Difference of viewing angle
 Distance is changed.
 When head rotates, objects move to stick in the field of view.
 Uncomfortable feeling of wearing eyeglasses at the first time.
Other concerns(2) Time Latency
 Latency between head
motion and image display
 When the head rotates:
 The image moves
 Oculus rift and Microsoft
hololens predict motion of
display and compensate
the delay.
Head Motion
Image transfer
Microsoft Hololens, an AR HMD
In AR, delay can be felt between
naked eye image and displayed image
→ more severe.
Pros & Cons of HMD / HMD
 Users can walk freely /
 Users can hide their bodies, meaning they can “deceive”
themselves. Becomes robust to latency and coordinate distortion.
/
 Heavy and feeling of being caged /
 Face is hidden, meaning two way communication is difficult /
 Design of large field of view is quite difficult /
Augmented Reality (AR) and See-Through HMD
 Overlap virtual world (CG image) and the real world
 Video See-Through
 Optical See-Through
Capture the real world by camera.
Use half-mirror & optically overlap
See-Through HMD (video see-through)
Problem of AR (1) Focal distance
 HMD image is always at the same distance.
 Distance of real world object is arbitrary
 User can’t clearly observe the two simultaneously.
 Video see-through partially solved the problem, but the real world
image is different due to large depth camera.
Problem of AR (2) Occlusion
(A) Ordinary HMD
(B) Ideal occlusion
(C) See-Through HMD
(D) Ground fixed display (projector and large screen)
Solution of Problem of AR(2) Occlusion
Kiyoshi Kiyokawa et.al. 2000
25
HMD Retina scan display
 Washington university, HIT Lab(‘99)
 Scan retina by laser beam
 Image focus by the eye lens is unnecessary
 Problem of focal distance is solved.
C&D Electronics
Red Laser
Diode
Delivery Optics
Argon
Laser
Scanners
AO Modulators
http://www.hitl.washington.edu/projects/vrd/
Retina Scan display by Brother Inc.
MEMS Light scanning Relay lens
device
Image on retina
Sync signal
rays
Pupil
Retina
Image signal
Light source
Production as AiR Scouter
http://www.brother.co.jp/product/hmd/wd100ga/
Retina Scan display by Brother Inc.
http://www.youtube.com/watch? v=CYBw-5plmmI
28
Head Mounted Projector by Retroreflector
http://projects.tachilab.org/rpt/
Model 1: 1998
Model 2: 1999
Model 3: 2003
What is retro-reflector?
 Glass balls with index of refraxtion=2
 Or, Cube type (Corner Cube)
 Any incident beams will come back to the same direction.
インタラクティブ技術特論
RPT: Retro-reflective Projection Technology
•Use retroreflector and projector
•Problem of focal distance is solved.
•Problem of occlusion is solved.
•Stereoscopic image can be presented
Tracking methods for HMD or human motion
 mechanical
 magnetic
 Optical
 Accelerometer, gyroscope, magnetometer
Magnetic trackers
Polhemus Fastrak
Ascension Flock of Birds
Mechanical
 Ivan Sutherland (1968)
1st HMD was
see through
Augmented
Reality ⇨
will mention later
Potential meter
Graphics
Reflecting
head orientation
35
Magnetic Position Sensing
Put AC voltage on three transmitter
coils one by one.
Voltage on three receiver coils results
nine voltages
The length of the vector → position
Direction of the vector → orientation
receiver
1/3 or Transmitter
Optical
 Opto Trak
Northern Digital Inc.
Maximum 2D Accuracy
Maximum 3D Accuracy
Maximum update rate
Resolution
0.1 mm
0.15 mm
4600 Hz
0.01 mm
• LED maker emit light
• position sense diode measure
direction of light source
• Estimate maker by triangulation
(三角測量)
Image on immersive projection displays
 Also update based on view point.
CAVE
3D display
 Depth cue
 Monocular cues, With single eye

Experience

Accommodation

Motion Parallax
Update image based on view point
 Binocular cues, With two eyes

Vergence eye movement

Binocular disparity
Different images for each eye.
→ Aims to show image based on view point.
Meaning of update based on view point.
 Difference between
TV and window
 Update image
based on view point
=
window to
virtual world.
ＴＶ
Window
Binocular display
 Present different image to left and right eyes.
 Stereo display
41
Anaglyph
 With red and cyan (green + blue) glasses
 Blue and yellow(red + green) is also possible
 binocular rivalry (
blinking by turns.
) tends to occur. Left and right images
Polarizer
Polarizer film
polarization preserving
projection screen…
is not very common.
Reflection type:
Silver screen
Transmission type:
Near to transparent
and no fiber.
You have to test then
to choose.
Polarizer film
Wave length band pass filter
 User different wave length for each eye
H. Jorke, A. Simon and M. Fritz 2008
Time-sequential method
 Liquid crystal shutter glass
 Battery is needed
 One of lens comes to dark.
 Synchronized by IR emitter.
 High refresh rate is required
 For binocular→120Hz is good
 Liquid crystal on Projector/Monitor
 No battery polarized glasses are enough
 One projector can present left and right images
 3D TV with glass usually show 60Hz for monocular,
Show image during 1/240 second.(L→dark→R→dark)
Naked eye (glass less) 3D display
 Volume scan display
Display emits light from 3D object’s shape.
 Varifocal mirror display
 Swept-volume display
 (Super) multi view display
Show images corresponding to view point position
 Integral Photography
 Parallax barrier
 Lenticular lens
Volume scan display
 Varifocal mirror display
 Swept-volume display
ＣＲＴ display
Varifocal mirror
Volume scan display
 Swept-volume display
Volumetric 3D Display by Actuality Systems
Volume scan display
 Lighting air
Super strong IR laser makes
super strong electric field
at the focal point.
→ air comes to plasma
→ emitting light
Lighting air with femtosecond (10 -15 sec) laser
50
Naked eye, binocular 3D display
 Lenticular lens
 Parallax barrier
Parallax barrier
Aperture / Slit
Image
Right eye
Image
Left eye
L
R
Lenticular lens
 For cell phones and LCD monitor
 View point must be fixed
FIY: Nintendo 3DS like 2D/3D switch
Block rays
TFT LC
LC for 3D
Parallax
barrier
Back light
Back light
 Liquid crystal layer for parallax barrier
2D/3D mode change
http://www.sharp.co.jp/products/device/about/lcd/3d/index.html
Multi viewpoint by Lenticular lens
 For left and right direction
vertical viewpoints are omitted.
 9 view point glassless 3D by
Toshiba
http://www.toshiba.co.jp/regza/option/gl1/quality.html より
Binocular display
by Lenticular lens
L
R
Lenticular lens
Image
 Many image pixels for many
viewpoint. One can move view
point
Integral photography
 Photograph with fly’s eye lens (
)
Lens
 The color of each lens differ for directions
Image on the film
Reproducing light field (
,
)
 Problem on volume scan display
Hidden line removal
Transparent,
backside can be seen is impossible
 Integral Photography reproduce light filed.
 Position and direction of rays (light field) is reproduced
The color and brightness differs
in direction at each pixel.
Example of reproduction of light field
 Cylindrical light field display
No transparency problem
RePro3D (T. Yoshida et al. 2010)
Projector array
Retroreflector
Half mirror
Projector array and
retroreflector (再帰性反射
材) generate eye position
dependent images.
http://www.jst.go.jp/pr/announce/20101012/index.html
Light field displays
Interactive 360
Light Field Display by Paul Debevec
Light field displays
60
Hologram
not a “holographic display”, real horography
 Diffraction grating reproduce light field
Recording a hologram
(Making diffraction grating)
Laser light
Reconstructing a hologram
Holograms
Explanation of hologram by equations
 Electric filed of a coherent light wave can be written as
𝑈 = 𝐴 𝑥, 𝑦, 𝑧 sin(𝜔𝑡 + 𝜙(𝑥, 𝑦, 𝑧)) = Re 𝐶 𝑥, 𝑦, 𝑧 𝑒 𝑖𝜔𝑡
(𝐴, 𝜙 are real numbers, C is a complex number)
𝑈𝑜 : reflection from object, 𝑈𝑅 :reference light, 𝑈𝐻 light from hologram
 Recording
𝑇, Transparency of the film
is proportional to light intensity on the film
𝑇 = 𝑘 𝑈𝑜 + 𝑈𝑅
2
= 𝑘 (𝑈𝑂 𝑈𝑅∗ + 𝑈𝑅
2
𝑈𝑅
𝑈𝑜
𝑈𝑅
+ 𝑈𝑂 2 +𝑈𝑂∗ 𝑈𝑅 )
 Play
𝑈𝐻 = 𝑇𝑈𝑅 = 𝑘𝑈𝑂 𝑈𝑅
2
𝑈𝐻
+ 𝑘 𝑈𝑅 2 𝑈𝑅 + 𝑘 𝑈𝑂 2 𝑈𝑅 + 𝑘𝑈𝑂∗ 𝑈𝑅2 )
 The first term is proportional to 𝑈𝑂 (reflection from object) = the
hologram image.
63
Pseudo 3D by 2 stacked images
 Space Illusion
 DFD (Depth Fused 3D Display) (NTT lab invented)
Front image plane
Back image plane
Viewer
2D image
3D image is
perceived
2D image
http://www.ntt-it.co.jp/goods/idp/dfd/principle.html
Pulfrich Effect
(another illusion for 3D)
Fast
Slow

Put eyeglasses with two different darkness for each eye

Different brightness generates temporal difference

Horizontal motion of the movie causes disparity, generates 3D feeling
Is 3D display really necessary?
 Maybe, but not for all works
 Yet too expensive, and contents are limited.
 To “observe” something, resolution is more important than 3D.
(You can observe with single eye!)
 However,
 To handwork in a virtual space, “distance” perception between
myself and the CG object is critically important.
Illusion by floating image

When the image is floating in
the air, we feel it as 3D
 3D images are float from the
display. Real 3D displays also
make floating images.
 When we see a floating image,
we feel it is an 3D object not
an picture on a wall
3D image
Display plane
Floating Vision
, 2008)
Image on display
Micro Lens arra
http://www.schaft.net/n00bs/201
0/02/24230148.html
Floating image
,2008)
http://www.youtube.com/watch?v=Wzx9zid_FoA
Fog Screen
http://www.fogscreen.com/
Water drop screen
71
Water drop multi viewpoint
72
(Rayleigh scattering)
(Mie scattering)
 Rayleigh scattering: particle size is smaller than 1/10 of wave
length.
 Mie scattering : particle size is larger than wave length
The larger particle makes the more transmission
Wave length of light: 0.4μm
Cloud:3
0.7μm
10μm, Rain drop:0.1mm
Rayleigh scattering
5mm
Mie scattering
73
Half transparent screen (completely different from half mirror)
http://www.youtube.com/watch?v=YH7S0lQ94nc
http://www.youtube.com/watch?v=rqg4Eun7fgs
Lumisight Table (Kakehi et al., 2003)
 Light control film
“Lumisty”: works both as
diffuser and transparent
film for different angle.
Viewer
Lumisty
Glass
Transparent
Scattered
Light control film Lumisty
Scatter transmission
A section
observation
Straight transmission
76
Lumisight Table (Kakehi et al., 2003)
 4
Different images for different user

Simultaneous motion analysis
is possible using transparency
インタラクティブ技術特論
Using eye movement
 2 kinds of eye motion
 Smooth Pursuit
（滑動性追跡眼球運動）
 Saccade(跳躍性眼球運動)
LED sign board using smooth pursuit
Avix Polevision
http://www.youtube.com/watch?v=KhpMzNYetis
Saccade Based Display (Watanabe et al)
 Saccade makes large jump
 Writing image at that time: one LED light
 (You can experience it at
Odaiba Mediage SonyExplorascience
5F
Present image at the instance of saccadic eye movement, using linear
LED array
http://www.junji.org/saccade/index.html
Saccade Based Display (Watanabe et al.)
http://www.youtube.com/watch?v=d_pjvSt3w18
インタラクティブ技術特論
Mini Test
100
Answer all questions within 50 words
1. HMD
Explain the role of convex lens in HMD.
2.
Explain how to realize full -color stereoscopic display by wavelength filter.
3.
Explain by figure how to achieve parallax by lenticular lens
4.
Explain by figure how to achieve parallax by barrier.
5.
Explain Pulfrich effect
6. AR
HMD
What are two types of HMD for AR?
7. AR
Explain problem related to focal distance in AR system
8. AR
Explain problem related to occlusion in AR system.