Computational Holography:
The real 3-D by fast wave-field rendering in ultra high resolution
Kyoji Matsusima*, Masaki Nakamura*, Sumio Nakahara*, and Ichiroh Kanaya***Kansai University, Japan; **Osaka University, Japan

2. Fast Wave-field Rendering

Fig. 1: Venus by Computational Holography

1. Introduction
James Cameron’s Avatar pioneered 3-D films inpractical meaning. All audiences of the movie werehappy even though their eye points were fixed
when they were watching the movie. However,there are certain area that fixed eye points are notacceptable. This is why the authors focus on
Computational Holography (see Fig. 1).
Holography is a technique that allows thelight scattered from an object to be recorded andlater reconstructed so that it appears as if the object
is in the same position relative to the recording
medium as it was when recorded [Wikipedia]. Oneof advantages of holography is that it provides full3-D view, meaning that viewers can see different
views of the object from the corresponding view
angles.
The computational holography (computergenerated holography) has long history and isoften called an ultimate 3-D rendering technology
since it produces not only sensation of depth but
also lightwave from the rendered objects
themselves. However, we must face difficulty of thecomputationalholography.
Synthesizing
holography has been quite difficult due to its heavy
load of computation. To illustrate, a stamp-sizedsynthesized holography requires 4 billion pixels(216 x 216 pixels). There have not been any practicaltechnique in computing such ultra high resolution
light field so far.
The authors propose a polygon/silhouettebased computational holography that overcomes awall of that computational complexity [1]. Thismethod numerically generates a lightwave of
surfaces of arbitrary objects, whose shape is given
in a set of vertex data of polygonal facets. Occluded
areas of the scene are correctly removed bycomputing silhouette of the objects. The authors
also propose a segmented frame buffer that canhandle very large wave-field that cannot fit in acomputer’s memory of today.
Copyright is held by the author / owner(s).
SIGGRAPH 2010, Los Angeles, California, July 25 – 29, 2010.
ISBN 978-1-4503-0210-4/10/0007

The authors propose polygon/silhouette-based wavefield rendering technique for accurate and fast
rendering of lightwave. This technique computes
wave-field propagation from small facets and thenintegrates the all contribution from the facets.
The wave-field doesn’t obey Kajiya’s
rendering equation. Instead of conventional raytracing, complex amplitude is computed. For
reducing complexity of the integral and hiding
back-faced/occluded areas, the silhouette of theobject is firstly computed and used for culling
unnecessary fields.
To save working memory of the integral,frame buffer is segmented in reasonable size. At
this stage contributions of each facets to theselected segment is estimated and non-contributing
facets are marked as ignorable (see Fig. 2). The
computing of lightwave propagation is then done
so that final wave field is drawn on the frame
buffers. Those stages can run simultaneously on
multi processors with a shared memory.
The authors demonstrate implementationof a large-scale computational holography, venus,
produced by a laser lithography shown in Fig. 1.

4. Conclusion
The authors proposed large-scale full-parallax
computacional holography and demonstrated
venus for its feasibility. The future works include
importing rendering technique in CGs.

Acknowledgement
The mesh data for the venus object is provided courtesyof INRIA by the AIM@SHAPE Shape Repository. Thiswork was supported by the JSPS.KAKENHI (21500114).

References[1] K. Matsushima, S. Nakahara: Extremely high-definition
full-parallax computer-generated hologram created by thepolygon-based method; Applied Optics, Vol. 48, No. 34, pp.
54-63, 2009.

Fig. 2: Subdivision of Wave-field Computation