• Title, Summary, Keyword: CGH

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FImplementation of RF Controller based on Digital System for TRS Repeater (실시간 디지털 홀로그래피를 위한 고성능 CGH프로세서)

  • Seo, Young-Ho;Choi, Hyun-Jun;Kim, Dong-Wook
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.11 no.8
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    • pp.1424-1433
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    • 2007
  • In this paper, we propose a hardware architecture to generate digital hologram using the modified CGH (Computer Generated Hologram) algorithm for hardware implementation and design to FPGA (Field Programmable Gate Array) platform. After analyzing the CGH algorithm, we propose an architecture of CGH cell which efficiently products digital hologram, and design CGH Kernel from configuring CGH Cell. Finally we implement CGH Processor using CGH Kernel, SDRAM Controller, DMA, etc. Performance of the proposed hardware can be proportionally increased through simply addition of CGH Cell in CGH Kernel, since a CGH Cell has operational independency. The proposed hardware was implemented using XC2VP70 FPGA of Xilinx and was stably operated in 200MHz clock frequency. It take 0.205 second for generating $1,280{\times}1,024$ digital hologram from 3 dimensional object which has 40,000 light sources.

Computer Generated Holography 기술 동향

  • Park, Jae-Hyeong
    • Information and Communications Magazine
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    • v.34 no.2
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    • pp.49-58
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    • 2017
  • 본고에서는 Computer generated holography (CGH) 기술에 대하여 알아본다. CGH는 3차원 물체에 대한 복소 광파를 계산하는 기술로서 홀로그래픽 디스플레이의 콘텐츠를 생성하는 핵심 기술 중 하나이다. 본 고에서는 대표적인 CGH 기술들인 점광원 기반 CGH, 삼각형 메쉬 기반 CGH, 광선 분포 기반 CGH, 다중 면 기반 CGH 기법들의 원리를 살펴보고, CGH의 최근 기술 동향을 알아본다.

Realization of the multi-phase level CGH according to the multi-channel encoding method using a PAL-SLM (PAL-SLM을 이용한 다채널 부호화 방법에 따른 다위상형 CGH의 광학적 구현)

  • Jung, Jong-Rae;Baek, Woon-Sik;Kim, Jung-Hoi;Kim, Nam
    • Korean Journal of Optics and Photonics
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    • v.15 no.4
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    • pp.299-308
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    • 2004
  • We proposed more efficient encoding methods that can design a multi-channel multi-level phase only computer-generated hologram(CGH) that can reconstruct many objects simultaneously without a conjugate image. We used a fabrication technique for the pixel oriented CGH for designing the pattern of the proposed multi-channel CGH. We investigated the difference of the optical efficiency(η), mean square error(MSE) and signal-to-noise ratio(SNR) of multi-channel CGHs that were designed by three kinds of encoding methods according to the number of quantization phase levels, and we estimated the performance of the pattern of the proposed multi-channel CGH. Generally, as the number of input objects' reference patterns stored in the CGH is increased, the reconstruction quality of the CGH is degraded. But we observed through computer simulation that the diffraction efficiency of the 1-ch CGH is 70%, and those of the 2-ch, 4-ch, 8-ch CGHs are 62%, 62% and 63%. Therefore we found that the diffraction efficiencies of the multi-channel CGHs using the newly proposed encoding method are similar to that of 1-ch CGH. We implemented the CGH optically using a liquid crystal spatial light phase modulator that consisted of a PAL-SLM efficiently coupled with a XGA type LCD by an optical lens and an LD for illuminating the LCD. We discussed the output images that are reconstructed from the PAL-SLM.

Protective Effects of Branched-chain Amino Acid (BCAA)-enriched Corn Gluten Hydrolysates on Ethanol-induced Hepatic Injury in Rats (알코올성 간 손상을 유발한 흰쥐에 대한 고 분지아미노산 함유 옥수수 단백가수물의 간 기능 보호효과)

  • Chung, Yong-Il;Bae, In-Young;Lee, Ji-Yeon;Chun, Hyang-Sook;Lee, Hyeon-Gyu
    • Korean Journal of Food Science and Technology
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    • v.41 no.6
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    • pp.706-711
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    • 2009
  • Hepatoprotective effects of corn gluten hydrolysates (CGH) were investigated in rats orally treated with ethanol (30%(v/v), 3 g/kg body weight/day) for 4 weeks. Six-week old Sprague-Dawley male rats were divided into four dietary groups: normal diet (N), alcohol diet (E), E+CGH 1% diet (CGH-1%), and E+CGH 3% diet (CGH-3%). Body weights and liver indices were not significantly different among the four groups. However, food intakes were lower in the CGH groups than in the normal group (p<0.05). The administration of CGH significantly reduced serum alkaline phosphatase activity by 30% compared to the alcohol diet group. Among the antioxidative enzymes assessed, catalase activity was significantly decreased by 79% in the CGH diet groups compared to the alcohol diet group. In comparison to the alcohol-treated group, aldehyde dehydrogenase activity was increased by 20%, while microsomal ethanol oxidizing system activity was decreased by 20% in the CGH-treated groups. Furthermore, the area under the curve of the blood acetaldehyde concentration versus time profile after the administration of ethanol was significantly lower for the CGH rats than for the ethanol or asparaginic acid treated groups. Thus, CGH seems to offer beneficial effects by protecting against ethanol-induced hepatotoxicity by improving the acetaldehyde-related metabolizing system.

VLSI Architecture for Computer-Generated Hologram (컴퓨터 생성 홀로그램을 위한 VLSI 구조)

  • Seo, Young-Ho;Choi, Hyun-Jun;Kim, Dong-Wook
    • The Journal of Korean Institute of Communications and Information Sciences
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    • v.33 no.7C
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    • pp.540-547
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    • 2008
  • In this paper, we proposed a new VLSI architecture which can generate computer-generated hologram (CGH) in real-time and implemented to hardware. The modified algorithm for high-performance CGH was introduced and re-analyzed (or designing hardware. from both numerical and visual analysis, the infernal number system of hardware was decided. CGH algorithm and precision analysis enabled to propose a new cell architecture for CGH. The operational sequence was analyzed with the architecture of CGH cell and the characteristics of the modified CGH algorithm, and finally the pipelined architecture and the operational timing were proposed.

Null computer generated hologram test for measurement of parabolic mirror (Null CGH를 이용한 포물면경 형상 측정)

  • 김태희;김성하;문일권;이윤우
    • Korean Journal of Optics and Photonics
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    • v.13 no.6
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    • pp.537-542
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    • 2002
  • Null tests using two different kinds of null corrector have been discussed. A parabolic mirror was used as a surface under test. After designing, encoding, and fabricating the CGH (computer generated hologram), the null CGH test was performed. An autocollimation test was also performed using a flat mirror. The reliability of the null CGH test has been discussed by comparing the result obtained by both null tests.

Extremely High-Definition Computer Generated Hologram Calculation Algorithm with Concave Lens Function (오목 렌즈 함수를 이용한 초 고해상도 Computer generated hologram 생성 기법)

  • Lee, Chang-Joo;Choi, Woo-Young;Oh, Kwan-Jung;Hong, Keehoon;Choi, Kihong;Cheon, Sang-Hoon;Park, Joongki;Lee, Seung-Yeol
    • Journal of Broadcast Engineering
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    • v.25 no.6
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    • pp.836-844
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    • 2020
  • A very large number of pixels is required to generate a computer generated hologram (CGH) with a large-size and wide viewing angle equivalent to that of an analog hologram, which incurs a very large amount of computation. For this reason, a high-performance computing device and long computation time were required to generate high-definition CGH. To solve these problems, in this paper, we propose a technique for generating high-definition CGH by arraying the pre-calculated low-definition CGH and multiplying the appropriately-shifted concave lens function. Using the proposed technique, 0.1 Gigapixel CGH recorded by the point cloud method can be used to calculate 2.5 Gigapixels CGH at a very high speed, and the recorded hologram image was successfully reconstructed through the experiment.

RAN-aCGH: R GUI Tools for Analysis and Visualization of an Array-CGH Experiment

  • Kim, Sang-Cheol;Kim, Byung-Soo
    • Genomics & Informatics
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    • v.5 no.3
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    • pp.137-139
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    • 2007
  • RAN-aCGH is an R GUI tool for the analysis and visualization of array comparative genomic hybridization (array-CGH) experiments. The tool consists of data-loading, preprocessing for missing data, several methods for statistical identification of DNA copy number aberration, and visualization of the copy number change. RAN-aCGH requires a single input format, provides various visualizations, and allows the addition of a new statistical method, all in a user-friendly graphic user interface (GUI).

Novel Optimization Method of Phase-Only Computer-Generated Hologram Using the Phase-Shift Characteristic (위상천이특성을 이용한 새로운 Phase-Only CGH 계산)

  • Kim, Tae-Hyeon;Kim, Bong-Sik;Park, Woo-Sang
    • Korean Journal of Optics and Photonics
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    • v.27 no.3
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    • pp.101-105
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    • 2016
  • In this study we propose the novel optimization method of the phase-only computer-generated hologram (CGH), to improve calculation speed compared to the conventional method. While the conventional method is calculated using numerical analysis, the novel method is calculated using the phase-shift characteristic of Fourier transformation. In addition, the selectivity of noise filtering lets it decrease the calculation time. The validity of the reconstructed image using the novel method is verified by comparing simulation results to ideal and conventional data, and the improvement of texture and sharpness of the reconstructed image is confirmed by simulation.

Analysis of Reconstructed Images of Computer Generated Hologram Formed according to Grating Modulation Methods (회절격자의 변조방식에 따라 형성된 CGH의 재생 영상 분석)

  • Jeong, Man-Ho
    • Korean Journal of Optics and Photonics
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    • v.19 no.5
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    • pp.360-364
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    • 2008
  • The diffraction efficiencies of gratings are affected by the inner structure which is determined by modulation type. CGH (Computer generated Hologram) basically uses the principles of a diffraction grating. As like as the diffraction gratings the patterns recorded in the CGH are different according to modulation methods which result in the performances of the reconstructed images. In this paper, on this fact CGHs are recorded according to sinusoidal and rectangular modulation methods and the characteristics of reconstructed images are analyzed. Also the reconstruction performances of the amplitude and phase, phase-only and binary phase CGH are analyzed.