International Workshop on Holography and related technologies (IWH2016), Jiaoxi (Taiwan), (2016.11.12).

Full-color high-definition CGH employing RGB color filters
Kyoji Matsushima and Yasuhiro Tsuchiyama
Department of Electrical and Electronic Engineering, Kansai University,
Yamate-cho 3-3-35, Suita, Osaka 564-8680, Japan

1. Introduction
For last several years, we have presented very large-scaled computer-generated holograms (CGHs) called
high-definition CGHs (HD-CGHs), which reconstruct full-parallax high-quality 3D images1-3). However,these HD-CGHs could reconstruct only monochromatic images. Recently, we proposed the technique for
their full-color reconstruction using RGB color filters and simulation to design appropriate filter properties4,5).
The techniques make it possible to create high-quality full-color HD-CGHs6).
2. Principle and techniques
Our HD-CGHs work well as reflection hologram because their fringe pattern made of Cr thin films. RGB
color filters are attached to each RGB fringe block, as shown in Fig.1. Here, gaps of the fringe, called guard
gap, are made for increasing position tolerances of the filters as in Fig.2. One of key techniques is to use amulti-chip type white LED for the illumination light source. Fairly narrow spectra are obtained fromcombination of the light source and filters, as shown in Fig.3 (b). We adopt a vertical stripe pattern for theRGB color filters in order to avoid overlapping light diffracted by the filters with the reconstructed object
image, because the light source is usually placed below the object for gaining higher diffraction efficiency.
3. Optical reconstruction and conclusion
The RGB color filters used are fabricated by the same technique as that of LCD panels. The filter properties
are shown in Fig.3 (a). These properties are designed through the simulation technique4,5). An example of
optical reconstruction and parameters of the full-color HD-CGH is shown in Fig.4 and Table 1, respectively.
The HD-CGH is composed of 16 G pix, the fringe pattern Table 1 Parameters of the fabricated HD-CGH
is generated by using the polygon-based method7) and theNo. of fringe pixels
131,072  131,072
silhouette method with the switch-back technique3).
Pixels pitches
0.8 m  0.8 m
Acknowledgement
Size10.5  10.5 cm2
The authors would like to thank Prof. Sakamoto and Fringe type
Binary amplitude

Metallic fringepattern

Fringe pattern

Pixel of fringe patternColor filters
Full-color 3D
imageColor filter

White light
Fig.1 The principle of full-color CGH
using RGB filters.

Guardgap
Fig.2 Color filters attached to the fringe pattern withguard gaps.

International Workshop on Holography and related technologies (IWH2016), Jiaoxi (Taiwan), (2016.11.12).

Nakahara for their useful suggestions. This work was financially supported by the JSPS KAKENHI Grant
Number 15K00512 and the MEXT strategic research foundation at private universities (2013-2017).

0.8GB

Effective illumination
intensity [a.u]Total LED intensity

1.0(LED intensity [a.u.])

Filter transmittance

References
1) K. Matsushima, S. Nakahara, “Extremely high-definition full-parallax computer-generated hologram
created by the polygon-based method,” Appl. Opt. 48, H54-H63 (2009).
2) K. Matsushima, H. Nishi, S. Nakahara, “Simple wave-field rendering for photorealistic reconstruction inpolygon-based high-definition computer holography,” J. Electron. Imaging 21, 023002 (2012).
3) K. Matsushima, M. Nakamura, S. Nakahara, “Silhouette method for hidden surface removal in computer
holography and its acceleration using the switch-back technique,” Opt. Express 22, 24450-24465(2014).
4) Y. Tsuchiyama, K. Matsushima, S. Nakahara, Y. Sakamoto, “A Simulation technique for selection ofcolor filter used for full-color high-definition CGH,” IWH2015, Th2-4 (2015).
5) Y. Tsuchiyama, K. Matsushima, S. Nakahara, Y. Sakamoto, “Full-color high-definition CGH using colorfilter and filter design based on simulation,” OSA Digital Holography & 3-D Imaging, DW5I.4 (2016).
6) Y. Tsuchiyama, K. Matsushima, “Full-color large-scaled computer-generated holograms using RGB
color filters,” to be published.
7) K. Matsushima, “Computer-generated holograms for three-dimensional surface objects with shade andtexture,” Appl. Opt. 44, 4607-4614(2005).

R0.6

0.4
0.2
0.0400450500

550

600

650

700

1.0R
G

0.8

B

0.6

0.4
0.2
0.0

400

450500550600650700

Wavelength
Wavelength(a)(b)
Fig.3 Spectra of (a) transmission of the fabricated RGB filter and (b) effective
illumination estimated by the white LED spectrum used for the light source.

WhiteLEDFig.4 Optical reconstruction of a HD-CGH named ‘Casino Chips’.