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Presenter: Dr. Xinxing Xia
Postdoc Research Associate, Being There Centre,
The University of North Carolina at Chapel Hill
E-mail: lygxia@gmail.com
Outline
Introduction
Floating LF 3D Display System
Large-scale LF 3D Display System
Conclusions
2
Spatial 3D display techniques attract a lot of
attention in recent years
– Volumetric 3D display
• Perspecta Spatial 3D SystemActuality Systems, Inc.
• Volumetric display system based on rotating LED array Zhejiang University
Introduction-3D Display
G.E. Favalora, Computer, 38[8], p.37–44 (2005).
G. E. Favalora, J. Napoli,et.al, Proc. SPIE 4712, 300-312 (2002).
X. Xie, X. Liu, and Y. Lin, J. Opt. A: Pure Appl. Opt. 11 045707 (2009).
X. Xie, X. Liu, and Y. Lin, SID’08 Technical Digest, p.1610-1613.
Y. Lin, X. Liu, X. Xie, X. Liu, H. Li, IMID’08 Technical Digest, p.1138-1141.
No Occlusion
3
Occlusion-capable multi-view display
– 198 views, Actuality Systems, Inc.
– View-dependent
An interactive 360-degree display
– 288 views, USC ICT
– Monochrome
Layered 3D display
– 7×7 views, Media Lab，MIT
– Limited view range
Introduction-3D Display
O. S. Cossairt, J. Napoli, et.al., Appl. Opt. ,46[8], p.1244–1250(2007).
A. Jones, et.al., ACM SIGGRAPH 2007 emerging technologies, August 05-09, 2007, San Diego, California.
G. Wetzstein, , et.al., ACM Transactions on Graphics, 30[4], 95, (2011) 4
Light field display
Volumetric display：reconstruct the location of spatial
points: V (x,y,z)
Light field(LF) display：reconstruct each ray emitting
from every spatial point: L (x,y,z,θ,φ)
– Horizontal only: L (x,y,z,θ)
Light Field Display
• Adding angular distribution
of the spatial points
• Occlusion-capable
5
Introduction
Penetrable 3D display floating in the air
How to carry out?6
System Configuration
– Color high-frame-rate projector
– Light field scanning screen
(directional-diffusing screen)
– Servo Motor and Driver
Floating 3D Display System
7
Three-chip high-frame-rate
projector
– Light source: RGB LEDs
– SLM: three-chip high-frame-
rate DMDs
Floating 3D Display System
4545 45
Main Board
D4100×3
DMD
DMD
DMD
Green LEDRed LED
Blue LED
X-cube
TIR
TIR
TIR
SMA×6
Workstation
High-frame-rate SLM
(TI Discovery 4100 Kit)
• Resolution：1024×768
• Frame rate：32000 fps (Max)
8
Light field scanning screen:
– Tilt angle：45°
– Diffusing angle：0.5°(H)×60°(V)
Synchronization of the screen
Floating 3D Display System
Servo driverHigh-frame-rate
projector
Initial phase signal
Angular pulse signal
9
Principle of the display
3D point
Image generator
Screen
( Here, )
Viewpoints region
(Here, )
: ( , , )P P PP x y z
( , , ) 0f x y z
0 0 0: ( , , )Q x y z
0z
( , ) 0g x y
2 2 2 0Vx y R
10
Principle of the display
Intersection of line QP and
viewpoints region to get one
viewpoint
Intersection of line VQ and
screen to get the image of
generator
0 0
0 0
( , ) 0
P P
x x y y
x x y y
g x y
: ( , , )V V VV x y z
0 0 0
0 0 0
( , , ) 0
V V V
x x y y z y
x x y y z y
f x y z
: ( , , )S S SS x y z
11
Observed image from one viewpoint
Principle of the display
Not a image projecting at
one time, but a combined
image of different projecting
sub images
2
+1 +1
2
( )V
V
N
V i j i j i j i j i j
j N
I I S T T S
12
Scanning from SiTi to Si+1Ti+1
Where, ( arcsin( ))V S VN ceiling N R R
Common display zone
– Observed from all
directions horizontally
Cone-shape area:
– Bottom:
circle region with radius
of Rs;
– Height HC:
HC = Rsh/(Rs+Rv)
Principle of the display
13
14
The display prototype
Experiments & Results
Prototype system
specification
Size of the utilized screen Φ400mm
Rotation speed of the
screen
1800 r/min
Projection distance 3000 mm
Projection image number
in one revolution
700
Frame rate of the projector 21000 fps
Image resolution 1024×768
Depth of projecting image 1 bit × 3(halftone)
Refresh rate of displayed
3D scene
30 Hz
The display on the prototype
– Reconstructed floating 3D scenes vs. Real box and doll
Experiments & Results
15
Displayed video
Experiments & Results
16
Display Week 2013,
Vancouver Convention Center,
Vancouver, BC, Canada17
Introduction- Large-scale LF Display
Large-scale Display No Moving Elements
How to carry out?
Large-scale 360-degree light-field 3D display
1818
System Configuration
– Projector Array
– Directional diffusing
screen
Large-scale 3D Display System
1919
Optical characteristics of the
directional-diffusing screen
– Horizontally:
• In a small angle
• Dependent on:
angular pitch and so on
– Vertically:
• In a large angle
• Ensure viewer to watch
the full image
Characteristics- Screen
x
y
z
2020
The spatial point Q reconstruction
– Ray to reconstruct the light , the same direction horizontally
– Light rays of a spatial point Q :
: the data of pixel
of the kth projector .
Principle of the display
PS QV
( , ) ( , )kI P i j
( , )kP i j ( , )i j
( , , )
( , , )
i f x y k
j g y z k
The relation between the point Q
and pixel (i, j) of the projecting
image from P
2121
The display prototype
Experiments & Results
Directional diffusing
screen
Projector Array
22
The display prototype
– Projector Array：DLP mini-projectors
• Resolution: 800×600
• Color depth: 24 bit
– Directional-diffusing Screen:
• 1.0°(H)×60.0°(V)
Experiments & Results
Size of the
diffuser
Number of
projectors
Radius of the
projector array
Projector’s
HFOV
3D Display
Zone
Φ3000mm 360(360°) 1700mm 17° Φ994mm
2323
The display on the prototype
– Large-scale 3D display
Experiments & Results
(a) Left view (b) Middle view (c) Right view
Photos taken from different directions
2424
The display on the prototype
– Large-scale 3D display vs. Real person
Experiments & Results
(a) (b)
The display system displaying different 3D scenes
2525
Displayed video demo
Experiments & Results
26
360-degree floating light field 3D display prototype
– A high-frame-rate color projector
– A flat light field scanning screen
– Mapping method from the rays of 3D points to the projecting images
360-degree large-scale light field 3D display prototype
– Ring-arranged projector array
– Cylindrical directional-diffusing screen
– Mapping method from the rays of 3D points to the projecting images
More improvement and research is needed
– Improving the color 3D image quality (grayscale, resolution, etc.)
– High-speed transmission of mass data for dynamic and interactive 3D display
Conclusions
27
These works about 3D displays are all finished in MOI, Zhejiang University.
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