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.