• Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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• 2009.05a
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• pp.211-213
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• 2009

Derivation of the phase error of hologram due to imperfection of a wave plate and analysis of the effect of phase error on 3-D image reconstruction of hologram are prexented.

• 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.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.16 no.11
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• pp.2355-2364
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• 2012

Recently, the novel loop-up table(N-LUT) method to solve the tremendous memory problem of the conventional look-up table (LUT) method as well as to increase the generation speed of hologram patterns has been proposed. But, as the resolution of an input 3-D object is enhanced, the number of object points to be calculated for generation of its hologram pattern also increases, which results in a sharp increase of the computation time. Therefore, in this paper, a new approach for fast generation of the hologram pattern of 3-D object images is proposed by using the block redundancy feature of 3-D object images and the N-LUT method. Experimental results show that in the proposed method the number of object points and the overall computation time have been reduced by 43.3 % and 47.9 %, respectively compared to those of the conventional method for the case of the $5{\times}5$ block size. These good experimental results finally confirm the feasibility of the proposed method.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.1005-1008
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• 2002

The authors introduce 3D display systems developed in our laboratories for recent ten years. Those are mainly realized by several technologies in holography: electro-holography. holographic stereogram, holographic optical elements (HOE) and hologram screen. We are currently focusing the development of 3D projection screen without glasses. Powerful directionality of the light beam is required for 3D projection screen unlike 2D type. We succeeded in achieving the superior diffractive efficiency of hologram screen that is based on the advanced volume holography. This technology is extensively useful to retrieve the Bragg condition of volume hologram in the three-dimensional space. Owing to this technology we could establish the principle of multi-view projection screen and have confirmed the case of 4 viewing points.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.11 no.7
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• pp.1267-1274
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• 2007

In this paper, we propose a digital watermarking algorithm for digital hologram generated by computer generated hologram(CGH) method. Digital hologram generated by a computer calculation(CGH) is one of the most expensive contents and its usage is being expanded. Thus, it is highly necessary to protect the ownership of digital hologram. In this paper two digital watermarking schemes are introduced hologram-domain and global 2DDCT-domain scheme. Proposed watermarking scheme showed very high imperceptibility and quite high robustness against the attacks. The purpose of this paper is to introduce these global 2DDCT based watermarking schemes. Thus, we expect that these and the contents in this paper can be very useful bases for the further digital watermarking schemes of the digital holograms.

• Journal of the HCI Society of Korea
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• v.8 no.2
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• pp.21-27
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• 2013

Recently, the use of floating hologram has increased in many different aspects, such as exhibitions, education, advertisements, and so on. Especially, the floating hologram that makes use of half-mirror is widely used. Nevertheless, half-mirror, unfortunately, cannot lead users to the perfect three dimensional hologram experience. Even though it can make the vision look to be up on the air, it does not have the capacity to display itself up on the air, which is the ultimate goal of hologram. In addition, it looks inconsistent when a real object is located behind the half-mirror in order to show the convergence of the two (object and the half-mirror). In this paper, we did the study on comparison of 3D space perception for the stereoscopic AR holography. At first, we applied stereoscopic technology to the half-mirror hologram system for the accurate and realistic AR environment. Then, the users can feel as if the real 3D object behind half-mirror and the reflected virtual image are converged much better in the 3D space. Furthermore, by using depth camera, the location and direction of graphics can be controlled to change depending on the user's point of view. This is the effective way to produce augmented stereoscopic images simply and accurately through half-mirror film without any additional devices. What we saw from the user test were applying 3D images and user interaction leads the users to have 3D spatial awareness and realism more effectively and accurately.

• Proceedings of the Korean Society of Broadcast Engineers Conference
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• 1999.06a
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• pp.219-226
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• 1999

Recently a study of Virtual-Reality becomes active. Expectation to 3-D reproduction technology rises with it. Electro-holography using Spatial light modulator (SLM) attracts attention, because natural 3-D animated image is provided. In this paper recent development of 3D-TV by Electro-holography is reported. We consider the conditions to holographic TV such as input, transmission and display systems. Also we consider about fast hologram calculation because It is important to execute hologram calculation at high speed to realize the real time electro-holography. Then we consider the possibility of real time holography.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2019.05a
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• pp.157-159
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• 2019

Hologram technology has been actively developed in terms of generation, transmission, and reproduction of 3D objects, but it is currently in a state of rest because of various limitations. Beyond VR and AR, the pseudo-hologram market is growing at an intermediate stage to meet the needs of new technologies. The key to the technology of hologram is to generate vast 3 dimensional data in the form of a point cloud, transmit the vast amount of data through the communication network in real time, and reproduce it like the original at the destination. In this paper, we propose a method to transmit massive 3 - D data in real - time and transmit the minutiae points of 3 - dimensional object information to reproduce the object as similar to original.

• The Journal of the Korea Contents Association
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• v.12 no.12
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• pp.597-604
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• 2012

In order to actualize the third dimension form, hologram is coming to attention because it has no restriction on viewing position and is capable of natural visual expression. Although hologram technology is the best method to embody 3D image without glasses, it is not commercialized due to several technological problems. Currently used hologram technology in concerts or exhibitions are images flashed on a 2-dimensional transparent screen by HD projectors which is similar to hologram technology, not truly same. In this research, we make 3D contents for Holographic projection and use these contents to present art that can interact with spectators. As a result of the exhibition, attendance showed satisfaction on inspection form, allowing spectators to move around the screen and view it both sides; moreover, they were enterprising to interact with the videos played according to their movements. Therefore, we are able to implement a sensible and spatio-temporal artwork along with interesting space production and represent a intimate and interactive space with the public.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.24 no.9
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• pp.1150-1157
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• 2020

It is expected that if a viewer feels the higher realism, it will increase efficiency at 3D hologram. Therefore, the purpose of this study is to analyze the effects of the evaluation factors on realism for digital signage using 3D holograms. For empirical analysis, the evaluation factors were derived and built up hypothesis(The evaluation factors of digital signage using 3D holograms will affect the realism). As a result of the experiment, Hypothesis 1 (Social presence) and 3 (Harmony with the space) were adopted while Hypothesis 2 (Graphic's elaboration) was rejected. Finally, research has shown that in order to improve the realism of digital signage using 3D holograms, the contents should be produced in consideration of presence so that the viewers could feel as if they were actually inside of contents rather than expressed extremely well made higher image resolution. Hence, the 3D hologram contents should be installed in a place where it would fit well with the space around it.