• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 2015.11a
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• pp.77-80
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• 2015

본 논문에서는 디지털 홀로그램(digital hologram)을 2 차원 비디오 압축기를 사용하여 압축하는 방법을 다룬다. 그 방법은 디지털 홀로그램을 다수 개의 부홀로그램(sub-hologram)으로 나누고, 각 부홀로그램을 2 차원영상화한 후 그 결과를 배열하여 동영상 시퀀스로 만들어 2 차원 동영상 압축기로 압축하는 방법이다. 각 부홀로그램을 2 차원 영상으로 만드는 방법으로 DCT(Discrete Cosine Transform)와 Fresnel 변환 변환(Fresnel Transform)을 사용하며, 다양한 크기의 부홀로그램을 고려한다. 2 차원 비디오 압축 방법으로는 H.264/AVC 와 HEVC 를 사용한다. 본 논문에서는 2 차원 영상 변환 방법, 부홀로그램의 크기, 그리고 2 차원 영상압축 방법에 따른 성능을 비교하고 분석한다.

• Journal of Korea Multimedia Society
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• v.22 no.10
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• pp.1208-1214
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• 2019

4th industrial age! 5G-based video content has changed rapidly. How do you view and understand VR/AR/MR/holograms in the age of convergent technology media represented by digital convergence in the 21st century beyond the modern visual system of Descartes? It predicts extension to an interactive visual system. This study proposes a methodology to visualize the Lacanian visual acuity after applying it to the L-System and to understand the visual system of the 21st century.

• Journal of the Optical Society of Korea
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• v.18 no.6
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• pp.698-705
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• 2014

We propose a new development for calculating a computer-generated hologram (CGH) through the use of multiple general-purpose graphics processing units (GPGPUs). For optimization of the implementation, CGH parallelization, object point tiling, memory selection for object point, hologram tiling, CGMA (compute to global memory access) ratio by block size, and memory mapping were considered. The proposed CGH was equipped with a digital holographic video system consisting of a camera system for capturing images (object points) and CPU/GPGPU software (S/W) for various image processing activities. The proposed system can generate about 37 full HD holograms per second using about 6K object points.

• Journal of Korea Society of Industrial Information Systems
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• v.23 no.4
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• pp.33-40
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• 2018

With the development of computer and video technology, a lot of contents are being produced as digital media methods to provide are being diversified and the intrest in digital media increases. Such contents are actively researched using human motion and user's information through camera or controller. Contents using user's information can be exposed to various people in public places and used as an advertisement. This paper proposes the character floating hologram system that is implemented using detection of user's height and motion. The purposed system detects user's height and motion from depth images and creates corresponding character from the detected data. Then it is represented using a floating hologram device. This system can be used for marketing, advertising and exhibition events using user information.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.14 no.9
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• pp.2091-2098
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• 2010

This paper proposes a hologram data compression scheme that uses the existing image/video compression techniques, in which the existing techniques are modified appropriately to fit to the characteristics of hologram. In this paper we use CGH as the hologram data. The proposed scheme uses the generation characteristics of a CGH to consist of a pre-processing, spatial segmentation of a CGH, frequency-transformation with 2D-DCT (2-dimensional discrete cosine transform), and motion estimation and residual image generation in the frequency-domain. It uses H.264/AVC, the lossless compressor BinHex, and a linear quantizer that we have made. From the experiments the proposed scheme showed the image quality of about 25.4 dB at the compression ratio of 10:1 and about 16.5dB at 90:1 compression ratio.

• Communications of the Korean Institute of Information Scientists and Engineers
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• v.29 no.12
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• pp.62-74
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• 2011

• Journal of Broadcast Engineering
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• v.19 no.6
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• pp.866-876
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• 2014

Generating of digital hologram of video contents with computer graphics(CG) requires natural fusion of 3D information between real and virtual. In this paper, we propose the system which can fuse real-virtual 3D information naturally and fast generate the digital hologram of fused results using multiple-GPUs based computer-generated-hologram(CGH) computing part. The system calculates camera projection matrix of RGB-Depth camera, and estimates the 3D information of virtual object. The 3D information of virtual object from projection matrix and real space are transmitted to Z buffer, which can fuse the 3D information, naturally. The fused result in Z buffer is transmitted to multiple-GPUs based CGH computing part. In this part, the digital hologram of fused result can be calculated fast. In experiment, the 3D information of virtual object from proposed system has the mean relative error(MRE) about 0.5138% in relation to real 3D information. In other words, it has the about 99% high-accuracy. In addition, we verify that proposed system can fast generate the digital hologram of fused result by using multiple GPUs based CGH calculation.

• 한국정보디스플레이학회:학술대회논문집
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• 2006.08a
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• pp.1553-1560
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• 2006

The idea of displaying hologram electronically has been existed since mid $1960^{th}$. But it is still in the beginning stage due to the lacks of proper means of displaying and recording, which will bear the large amount of data contained in the hologram though holographic video and digital holography have demonstrated the possibility of displaying and photographing hologram electronically. It is expected that holography based 3 dimensional imaging system will be introduced much later than that on multiview 3 dimensional imaging methods which are being developed to generate more realistic and natural image than high definition plane images.

• The Journal of Korean Institute of Communications and Information Sciences
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• v.34 no.6C
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• pp.604-610
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• 2009

This paper propose a digital watermarking method for digital contents which satisfies both the invisibility and the robustness to attacks to prohibit counterfeiting, modification, illegal usage and illegal re-production of video contents. This watermarking algorithm insert a watermark(digital hologram) by generated using Fresnel transform which improve the robustness. The inserting positions of the watermark choose by considering the frequency property of an image and a watermark. Also the amount of watermarking for watermark bit decide by considering the level of 2DDWT. This algorithm was implemented by C++ and experimented for invisibility and robustness with optical system. The experiment results showed that the method satisfied enough the invisibility of the inserted watermark and robustness against attacks. For the general attacks, the error rate of the extracted watermark was less than 15%, which is enough in robustness against the attacks.

• Journal of Broadcast Engineering
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• v.26 no.3
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• pp.296-307
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• 2021

A digital hologram (DH) is an ultra-high value-added video content that includes 3D information in 2D data. Therefore, its intellectual property rights must be protected for its distribution. For this, this paper proposes a watermarking method of DH using a deep neural network. This method is a watermark (WM) invisibility, attack robustness, and blind watermarking method that does not use host information in WM extraction. The proposed network consists of four sub-networks: pre-processing for each of the host and WM, WM embedding watermark, and WM extracting watermark. This network expand the WM data to the host instead of shrinking host data to WM and concatenate it to the host to insert the WM by considering the characteristics of a DH having a strong high frequency component. In addition, in the training of this network, the difference in performance according to the data distribution property of DH is identified, and a method of selecting a training data set with the best performance in all types of DH is presented. The proposed method is tested for various types and strengths of attacks to show its performance. It also shows that this method has high practicality as it operates independently of the resolution of the host DH and WM data.