A compressive approach to light field synthesis with projection devices. We propose a novel, passive screen design that is combined with high-speed light field projection and nonnegative light field factorization. We demonstrate that the projector can alternatively achieve super-resolved and high dynamic range 2D image display when used with a conventional screen.

1. A Compressive
Light Field Projection System
Matthew Hirsch1* Gordon Wetzstein1,2* Ramesh Raskar1
1MIT Media Lab
2now at Stanford University
*equal contribution

2. Raskar et al. 1998

4. 3D Theaters
Specialized Glasses
Specialized Projector
Specialized Screen

6. Projector

9. Glasses Free 3D Theaters
Cyclostereoscope, France, 1940-50s
Seymon Palovich Ivanov, Russia, 1935
Inventors & Filmmakers, 1950s

10. Mechanical Movement
Bogaert et al. 2010Cossairt et al. 2005

11. Multi-projector Glasses Free 3D
USC ICT – SIGGRAPH 2013 ETech Holografika

12. Anatomy of a Projector
Modulator
Projection LensDiffuse Screen
Viewer

13. Building a 3D Projector
Side View
Vertical-Only Diffuser

14. Building a 3D Projector
Lenticular

15. Building a 3D Projector

16. Our Approach

17. LIGHT FIELD PROJECTOR
Prototype Implementation

18. Prototype Schematic

19. Prototype Schematic
Illumination
Spatial Light Modulator
(LCOS)
Spatial Light Modulator
(LCOS)
Relay Lens
Projector Lens
Beamsplitter
Beamsplitter

20. Prototype

21. ANGLE EXPANDING SCREEN
Prototype Implementation

23. Angle Expanding Screen
Back
Front
Fresnel Lens
Lenticular (Long F)
Lenticular (Short F)
Vertical Diffuser
(Lenticular)

24. Laser Test

25. COMPUTATION
Non-negative Tensor Factorization

26. gt ¬ gt
FT
(bl (Yht ))
FT
(l (Yht ))+e
ht ¬ ht
YT
(bl (Fgt ))
YT
(l (Fgt ))+e
minimize bl - (Fgt ) (Yht )
t
å 2
subject to 0 £ g,h £1
l(x,u) = g(f(x,u)) h(y(x,u))
Top View
g h
YF
l
=
Light Field
l(x,u) g(f(x,u))
h(y(x,u))
t
å
vertical diffuser
inversion
Side View
tt
perceptual integration
convolution (diffusion &
aberrations)

31. Flexible Display Modes – Superresolution and HDR
conventional
screen
LightFieldProjector
projected signal
cos ( fg x )
cos ( fh x )
0.5 ( cos ( (fg+fh ) x) + cos ( (fg-fh ) x) )

33. More Details in the Paper & Supplement!
Matlab Source Code &
OpenGL Pseudo-Code
Compressibility
Convergence
Optics

34. Possible Extensions
Extended Field of View Coded Aperture Projection
Vertical stacking: • Higher rank
• Color projection

35. Limitations
• Color projection (e.g. multiple devices)
• Screen
• More angle expansion
• Larger size
• Less scattering and aberrations

36. A Compressive Light Field Projection System
Matthew Hirsch Gordon Wetzstein Ramesh Raskar
media.mit.edu/~gordonw/CompressiveLightFieldProjector/
See demo at Emerging Technologies!
Thanks to: Hisham Bedri, Silicon Micro Display, Vincent Lee,
Matthew O’Toole, Phil Surman

37. “standard” formulationalternate formulation
Low-rank Tensor Factorization

38. alternate formulation
forward projection (multiview rendering) back projection (projective texture mapping)
Efficient GPU Implementation
Tensor Factorization - Implementation