Digital holographic video M. Kujawiska, T. Kozacki Warsaw - - PDF document

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Digital holographic video M. Kujawiska, T. Kozacki Warsaw - - PDF document

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3D Stereo Media Liege, 8-10 December, 2010 Digital holographic video M. Kujawiska, T. Kozacki Warsaw University of Technology Real 3D project is funded by the European Community's Seventh Framework 3D StereoMedia, December 2010 INTRODUCTION

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3D StereoMedia, December 2010

Digital holographic video

  • M. Kujawińska, T. Kozacki

Warsaw University of Technology

Real 3D project is funded by the European Community's Seventh Framework

3D Stereo Media Liege, 8-10 December, 2010

3D StereoMedia, December 2010

INTRODUCTION True-3D = physical duplication of light distribution in a volume of interest

“True-3D”, in which none of the restrictions on the viewer exists due to physical duplication of light distribution, is more desirable and superior compared to stereoscopy; however such display systems are much more complicated. Holography is a sophisticated true-3D method.

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3D StereoMedia, December 2010

Holography

greek holos – whole (entire) grapho – write (record)

The two step method for lensless recording of 3D information about an object in the form of a complex amplitude

A(x,y)= Ao(x,y) exp(F(x,y))

Optical holography requires: coherent (laser) light, high resolution recording material

Goodman “Fourier Optics”

Object phase Object amplitude

Digital holography requires: Coherent light, high resolution and big aperture CCD/CMOS

3D StereoMedia, December 2010

Fundamental challenge in holographic video

Goal: achieving a high enough space-bandwidth product of capture and display system to meet the image size and view angle requirements for the viewer.  a large view angle is possible only with very small interference fringes (and thus small pixels),  a large image translates to a large aperture of CCD and light modulator

Therefore what’s necessary is a massive number of very small pixels.

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3D StereoMedia, December 2010

MIT holographic systems: Mark-I, II, III

Mark III based on surface acoustic wave (scanning replaced by HOE)  440 scan lines, 30 Hz

 80 x 60 x 80 mm3, 24 deg view angle

  • P. St.-Hilaire. Scalable optical architectures for electronic holography. In Ph. D. Thesis,

Program in Media Arts and Sciences, MIT, 1994.

Mark II 18 channel AOM+ bank of scanning mirrors

Controlled by custom based computer Cheops 150x75x150 mm3, 30 deg view angle

Mark I: 1D light modulation by AOM + mechanical scanning

3D StereoMedia, December 2010

See Real (2007)

  • S. Reichelt,et al. Large holographic 3D displays for tomorrowŠs TV and monitors - solutions, challenges, and prospects. IEEE Lasers and Electro-Optics Society,
  • 2008. LEOS 2008. 21st Annual Meeting of the, pages 194–195, 2008.
  • R. Häussler, A. Schwerdtner, and N. Leister. Large holographic displays as an alternative to stereoscopic displays. volume 6803, page 68030M. SPIE, 2008.

Approach: reconstruct only that part of the object wavefront that hits the eye pupil of observer. Vertical paralax only.

Separate observer window for each eye generated by spatial or temporal multiplexing

Observer window 20’’ prototype, 0.5 deg, eye tracking – matching Observer Window in real time

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QinetiQ: Active Tiling System

  • J. Hahn, H. Kim, Y. Lim, G. Park, and B. Lee. Opt. Express, 16(16):12372–12386, 2008.

Features:

For store and display CG holograms High frame rate of medium complexity

  • Electr. address EASLMs –image generator

Holograms written at high res. OASLM Parallel approach Monochromatic or frame –sequential-colour 1x4 channel AT unit Spatial multiplex 3x8 bilion-pixel Full-paralax Full-colour 3D image

3D StereoMedia, December 2010

Dynamic holographic stereogram

Joonku Hahn, Hwi Kim, Yongjun Lim, Gilbae Park, and Byoungho Lee. Wide viewing angle dynamic holographic stereogram with a curved array of spatial light modulators. Opt. Express, 16(16):12372–12386, 2008

Achieved viewing angle 22.8 deg (2008, Korea) LCOSes display holograms calculated from 2D images

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Conclusions from the overview The existing holographic systems are based

  • n CG holograms but holograms of real
  • bjects

Digital holography for 3D and 4D real-world objects’ capture, processing, and display OULU, Bilkent, WUT, EPFEL, BIAS, CNR Holoeye, LynceeTech, NUIM,

3D StereoMedia, December 2010

Real 3D Holographic video

Registration

Numerical CGH Optical Digital Holograms

Reconstruction

Numerical Optical

Data processing

  • Cal. Complex amplitude

Reduction of information Quality improvement Manipulation of 3D object

Cyfrowe hologramy

A/D: CCD/CMOS

3D static & dynamic scenes

Aim of EU project Real 3D

Digital holograms

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3D StereoMedia, December 2010

Model of Object/scene 3D/4D Complex amplitude distribution

  • f the object

wavefront Determination Γ(x,y,z) Fouriera Hol., Fresnela Hol., Stereogram, ...............

Data displayed: Computer generated holograms

Cloud of points Triangle mesh 2D images Photometric representation Coding, Processing Registration Konwersja C/A SLM Eye tracking module 3D scene visualization

Multi GPU systems (HORN6)

3D StereoMedia, December 2010

Real3D holographic video system

  • Application of inline Fresnel holograms
  • Capture of different perspectives of an object by

multiple high resolution CCD/CMOS cameras in circular configuration

  • Display of holograms by multiple phase-only

SLMs in circular configuration

  • Matching the parameters of capture and display

systems

  • Coding and compression of DHs for high quality

data transfer

  • Data processing of DHs into object phase data

for display at SLMs

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Capture system

  • Multi CCD system (6)
  • Circular configuration
  • Normal of CCDs directed

to object

Otherwise:

  • Optical field might not fill detector
  • Optical field might be nor recorded

due to high frequencies

  • Inline hologram registr.:

PSDH (static) Fresnel (dynamic)

  • best use of spatial bandwidth
  • but need to remove DC and TI
  • good 3Dperception

Basler piA2400 -12gm (2456x2058, 3.45mm)

3D StereoMedia, December 2010

Capture system 6 CCDs

Source : Impulse laser 6ns Problem low fill factor

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3D StereoMedia, December 2010

Capture system 6 CCDs

3D StereoMedia, December 2010

Removal of DC and twin image terms from inline holograms

Reconstruction of a single DH

Reconstruction

  • f inline hologram

Phase shifting holography Requires capture of at least 3 DH

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3D StereoMedia, December 2010

Display system– Illumination along normal

Advantage: the captured optical field is directly reconstructed on SLMs Disadvantage: complicated opto- mechanical realization Multi LCOS SLMs

Liquid Crystal on Silicon SLM Holoeye 1080P

Pixel size 8mm

3D StereoMedia, December 2010

Reconstruction system – single illumination direction

Advantages: Flexible system Easy to adjust and calibrate Problem: the phase function at SLMs should include the tilt LCoS display – HEO 1080P Phase only (res. 1080x1920, pp. 8mm)

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With tilt procedure

Wide angle tilt processing angorithm

Tilt 0° Tilt 10° Tilt 20° Tilt 30° Tilt 40°

Without tilt procedure With tilt procedure

3D StereoMedia, December 2010

Coupling the capture and display systems Mismatch in geometrical and optical features of both systems N1=N2 Wavelength Size of pixels

zreg

  • distance between object and detector,

lreg/rec

  • wave length used during registration and reconstruction

Dreg/rec

  • pixel size of CCD and SLM respectively

Reconstruction distance Transverse

reg rec rec reg reg rec

z z

2 2

D D  l l

Longitudinal Angular magnification

reg rec t

M D D 

2 t rec reg l

M M l l 

t reg rec

M M l l

 

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Holographic display: Main modules

Multi SLMs Module Control & Data Processing Illumination Observation

CPU

Naked eye observation Directional diffuser Through eyepiece Nd:Yag: l=532nm

3D StereoMedia, December 2010

Display

Configuration for FF=0.6 SLMs Mirrors

Colimator

SLMs & electronics Laser& electronics

Real images

  • hologram reconstruction

distance: 400 – 700 mm,

  • observation of real

(but imaginary) image

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Reconstruction of static object

3 different perspectives as seen by camera from combined image 6 views of different object perspectives as reconstructed by single SLMs

3D StereoMedia, December 2010

Simulations for newest JVC SLM

JVC SLM (simulation parameters)

Resolution: 8000 x 4000 pixels, pixel size 4.8 µm Distance between eyes db = 65 [mm], FF(for both capture and display) =1 i 6 SLMs Reconstruction distance: 1000 [mm],

Output:

VFOV = 111 [mm] No gaps Allowed a certain Observer’s movement

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3D StereoMedia, December 2010

Whish list

  • Increase aperture

(capture/display devices) and decrease the size of pixels

  • CCD/CMOS at flexible

substrate (circular configuration)

  • Solutions (optical+

numerical) for gaps problem

  • Increase the quality of

visualization the wavefront in space

  • Efficient solutions for

video capture and data transfer

3D StereoMedia, December 2010

Real 3D project is funded by the European Community's Seventh Framework Programme FP7/2007-2013 under grant agreement n° 216105

OULU (Finland) BIAS (Germany) PW (Poland) NUIM (Ireland) Holoeye (Germany) CNR (Italy) PFEL (CH) Linceetech (CH)