International Symposium on Display Holography 2018 (ISDH2018), Aveiro (Portugal), (2018.6.29).

Low-bits encoding of wave-fields for data-size reduction
in computer holography
Shoya Masuji, Kyoji Matsushima, Mitsuji Muneyasu
Department of Electrical and Electronic Engineering, Kansai University
3-3-35 Yamate-cho, Suita, Osaka 564-8680, JapanABSTRACT
For the last few years, high-definition computer-generated holograms (CGHs), composed of more than billions pixels,
have been expanding its scale, and the optical reconstruction has become clearer. In computer holography, light is treatedas a digital data, but storing and transmission of the data are difficult because of its huge data-size.
We have two choices to store and transmit CGH data. One is to hold the fringe pattern. Alternatively, we can hold thesampled wave-field of the objects or 3D scene. The data-size of a fringe pattern is considerably smaller than that of thesampled wave-field. But, when a CGH data is held as the fringe pattern, reconstruction parameters of the CGH, such as
the incident angle of illumination light, cannot be changed in the reconstruction system. In contrast, holding the sampled
wave-field has several advantages in terms of versatility, but the data-size is commonly eight times larger than that of thefringe pattern encoded with 8 bits gray-level.
In this paper, we propose a technique of low-bits encoding of a wave-field to compact the data of high-definition CGHs.
This technique uses nonlinear quantization algorithm that requires iterative optimization. However, encoding by theproposed technique is very fast, because we utilize the fact that the shape of amplitude histogram of a wave-field isalmost independent of the type and scale of the wave-field, and thus the quantization parameters can be pre-computed.
Actual high-definition CGHs created using the proposed low-bits encoding technique are demonstrated to confirm
validity of the technique.
Keywords: Computer holography, Computer-generated hologram, quantization, encoding

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fax +81-6-6368-0933

8 bit/sample, low-bits
encoding, (this work)

64 bit/sample