The 13th International Conference on 3D Systems and Applications (3DSA2022),Taipei(Taiwan)+online, Keynote Speech-1 (2022.11.24, Invited talk)

Advances in Large-scale Computer Holography
Kyoji Matsushima
Dept. of Electrical, Electronic and Information Engineering, Kansai University, Japan

Abstract
Traditional holography is not a modern digital technology because the holograms cannot be stored and transmitted with digital media. The nature of ahologram is the fringe pattern generated by optical interference with a reference wave. The origin of the concept of computer-generated holograms(CGHs), whose fringe patterns are calculated by computers, goes back to the days immediately after the realization of 3D imaging in optical holography.
However, CGHs comparable to optical holograms were not realized until recently. This is entirely due to the extremely large space-bandwidth product(SBP) required for quality holograms. The viewing angle of a CGH is mainly determined by the pixel pitches x and y of the fringe image. As anexample, when x = y = 0.6 m, the viewing angle of the CGH is 48° in blue color (488 nm). As a result, when we create a CGH with the dimensionsof a 40-inch high-definition television (88.4 cm × 49.8 cm), the number of pixels is approximately 1.22 T pix.
Over the past 15 years, we have developed computer holography to create quality CGHs for 3D imaging [1]. The maximum SBP has reachedapproximately 0.2 trillion as of August 2022 and is predicted to exceed 0.5 trillion within a year. These large-scale CGHs reconstruct not only
monochromatic images but also full-color images. The impressive full-parallax 3D images give an amazing sensation of depth to the viewer, which has
not been realized by other technologies.
We refer to full-parallax CGHs of more than 1 billion pixels as full-parallax high-definition CGHs (FPHD-CGHs). The first FPHD-CGH was TheVenus created in 2009 [2]. The fringe of The Venus was comprised of 4.2 G pix and was printed adopting laser lithography (see Sec. 15.3 in [1]). Theobject field was calculated using the polygon-based method [3]; only mutual occlusion between separate objects was processed in this CGH using thesilhouette method [4]. To realize FPHD-CGHs, although we have developed several numerical techniques in the field of wave optics [5–7], thecomputation time of The Venus was 48 h in 2009. Nowadays the same CGH can be calculated in 20 min and complicated self-occlusion can beproperly processed using the switch-back technique [8]. CG-modeled 3D objects are reconstructed with not only diffusive surfaces but also specularsurfaces [9,10]. Real objects can be incorporated into a 3D scene of virtual objects [11,12]. We can reconstruct FPHD-CGHs in full-color with the twomethods [13,14]. Recently, we have developed a new technique to create flipbooks of FPHD-CGHs [15].
Figures 1 and 2 show examples of the latest monochrome and color FPHD-CGHs composed of more than 0.1 T pix, respectively. The latter is thefull-color version of a monochrome CGH named Brothers, which was exhibited at the museum of the Massachusetts Institute of Technology in 2012[16]. The RGB color filters are used for the full-color reconstruction [11].
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K. Matsushima, Introduction to Computer Holography, (Springer, 2020).
34 cm
K. Matsushima, S. Nakahara, “Extremely high-definition full-parallax
Mobilecomputer-generated hologram created by the polygon-based method,” Appl.
phoneOpt. 48, H54-H63 (2009).
K. Matsushima: “Computer-generated holograms for three-dimensionalsurface objects with shade and texture,” Appl. Opt. 44, 4607-4614 (2005).
17 cm
A. Kondoh, K Matsushima, “Hidden surface removal in full-parallax CGHs
by silhouette approximation,” Syst. Comput. Jpn. 38, 53–61 (2007)
K. Matsushima, H. Schimmel, F. Wyrowski, “Fast calculation method for
optical diffraction on tilted planes by use of the angular spectrum of planewaves,” J. Opt. Soc. Am. A20, 1755-1762(2003).
Fig.1 Monochrome FPHD-CGH composed of 425,000 ×K. Matsushima, T. Shimobaba, “Band-limited angular spectrum method for
425,000 pixels with a pixel pitch of 0.8 μm × 0.4 μm.
numerical simulation of free-space propagation in far and near fields,” Opt.
Express 17, 19662-19673 (2009).
K. Matsushima, “Shifted angular spectrum method for off-axis numericalpropagation,” Opt. Express 18, 18453-18463 (2010).
K. Matsushima, M. Nakamura, S. Nakahara, “Silhouette method for hidden
surface removal in computer holography and its acceleration using theswitch-back technique,” Opt. Express 22, 24450-24465(2014).
H. Nishi, K. Matsushima, S. Nakahara, “Rendering of specular surfaces inpolygon-based computer-generated holograms,” Appl. Opt. 50, H245-H252(2011).
H. Nishi, K. Matsushima, “Rendering of specular curved objects in polygonbased computer holography,” Appl. Opt. 56, F37-F44 (2017).
K. Matsushima, Y. Arima, S. Nakahara, “Digitized holography: modernholography for 3D imaging of virtual and real objects,” Appl. Opt. 50, H278Fig.2 Full-color FPHD-CGH composed of 225,000 ×H284 (2011).
450,000 pixels with a pixel pitch of 0.8 μm × 0.4 μm.
K. Matsushima, N. Sonobe, “Full-color digitized holography for large-scale
holographic 3D imaging of physical and nonphysical objects,” Appl. Opt. 57, A150-A156 (2018),
Y. Tsuchiyama, K. Matsushima, “Full-color large-scaled computer-generated holograms using RGB color filters,” Opt. Express 25, 2016-2030(2017).
O. Kunieda and K. Matsushima, “High-quality full-parallax full-color three-dimensional image reconstructed by stacking large-scale computergenerated volume holograms,” Appl. Opt. 58, G104-G111(2019).
Press release, https://www.kddi-research.jp/english/newsrelease/2022/050901.html
K. Matsushima, S. Nakahara, “Stepping closer to the perfect 3D digital image,” SPIE Newsroom, (7 Nov. 2012).