• Journal of Korea Game Society
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• v.11 no.1
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• pp.47-57
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• 2011

Mobile based location-based service can normally be classified into four categories according to their dimensions of their screen layout: map-based, bird-eye view based, photo-based, and video-based. Specifically, video-based layout system combining AR technology has a appealing factor to users through the reality-based presence but normally requires sophisticated real-time image matching algorithms to represent the system. This paper provides a new location-based service by introducing mirror world to resolve the problem and implements its prototype. The proposed service does not need such algorithm and will effectively be useful for users to get the reality of the presence for any locations which is regardless of a user's real location.

• Transactions of the Society of Information Storage Systems
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• v.2 no.1
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• pp.43-49
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• 2006

Fractal/angle multiplexing is a $LiNBO_3$ crystal using a X-Y Galvano mirror, and the random access concept in fractal/angle multiplexing are discussed in this paper. First, the brief introduction of the designed holographic digital data storage system is presented. Then, the average access time concept for the storage system is newly defined, and the comparison of the average access time between the holographic storage and a conventional optical disk is performed. Second, the basic simulation and experiment to find the X-Y Galvano mirror dynamics are conducted. From this analysis, we find that the average access time in our HDDS which has 6 degree scan angle is about 5 msec. This result is very high performance when it compared with the average access time of a conventional optical disk. Finally, some recording results using fractal/angle multiplexing are presented, then, the relationship between bit error rate and angle mismatch for the each multiplexing are discussed.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2000.11a
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• pp.102-105
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• 2000

A simple digital control system has been developed for the frequency stabilization of an internal mirror He-Ne laser. The system is based on one chip microprocessor with embedded Basic interpreter. To stabilize the laser output frequency, the signal such as power difference or beat frequency between two modes is supplied and processed by a microprocessor, and control signal is fed to the heating coil would round the laser tube for adjusting the spacing of the laser cavity mirror. Newly developed frequency stabilization system is totally digitized. The system and the frequency stability performance are briefly described.

• 한국정보디스플레이학회:학술대회논문집
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• 2002.08a
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• pp.969-971
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• 2002

In this paper, we study the performances of optical system design using the 1 panel LCD without color filter for projection color television. We analyze the optical efficiency compare this system with 1 panel LCD system using the color filter, and work out a constraint condition of 1 panel LCD without color filter for optical design. We design a high brightness 1 panel optical system using a complex reflection mirror and suggest a method of the optical system design.

• Journal of the Korean Society for Precision Engineering
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• v.29 no.3
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• pp.247-252
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• 2012

This study has been focused on application of ELID mirror-surface grinding technology for manufacturing single crystal optic sapphire. Single crystal sapphire is a superior material with optic properties of high performance as light transmission, thermal conductivity, hardness and so on. Mirror-surface machining technology is necessary to use sapphire as optic parts. The ELID grinding system has been set up for machining of the sapphire material. According to the ELID experimental results, it shows that the surface of sapphire can be eliminated by metal bonded wheel with micron abrasives and the surface roughness of 60nmRa can be gotten using grinding wheel of 2,000 mesh in 4.5um, depth of cut. In this study, the chemical experiments after ELID grinding also has been conducted to check chemical reaction between workpiece and grinding wheel on ELID grinding process. It shows that the chemical reaction has not happened as the results of the chemical experiments.

• Journal of the Optical Society of Korea
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• v.16 no.3
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• pp.263-269
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• 2012

In this paper, we propose a new dual optical encryption method for binary data and secret key based on 2-step phase-shifting digital holography for a cryptographic system. Schematically, the proposed optical setup contains two Mach-Zehnder type interferometers. The inner interferometer is used for encrypting the secret key with the common key, while the outer interferometer is used for encrypting the binary data with the same secret key. 2-step phase-shifting digital holograms, which result in the encrypted data, are acquired by moving the PZT mirror with phase step of 0 or ${\pi}/2$ in the reference beam path of the Mach-Zehnder type interferometer. The digital hologram with the encrypted information is a Fourier transform hologram and is recorded on CCD with 256 gray level quantized intensities. Computer experiments show the results to be encryption and decryption carried out with the proposed method. The decryption of binary secret key image and data image is performed successfully.

• Journal of the Optical Society of Korea
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• v.10 no.3
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• pp.118-123
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• 2006

We present an optical security method for binary data information by using 4-step phase-shifting digital holography and we analyze tolerance error for the decrypted data. 4-step phase-shifting digital holograms are acquired by moving the PZT mirror with equidistant phase steps of ${\pi}/2$ in the Mach-Zender type interferometer. The digital hologram in this method is a Fourier transform hologram and is quantized with 256 gray level. The decryption performance of the binary data information is analyzed. One of the most important errors is the quantization error in detecting the hologram intensity on CCD. The greater the number of quantization error pixels and the variation of gray level increase, the more the number of error bits increases for decryption. Computer experiments show the results for encryption and decryption with the proposed method and show the graph to analyze the tolerance of the quantization error in the system.

• Journal of Multimedia Information System
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• v.8 no.1
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• pp.75-78
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• 2021

This paper will explain the importance of using interactive prototyping tools in the HCI design process. The Future of HCI education project performed by ACM SIGCHI shows that students recognize that prototyping, especially paper prototyping and interactive prototyping, are both very important. Two widely-used prototyping tools in academy, Balsamiq and Oven, will be compared and rated by students according to their preferences. We choose the Balsamiq as our design tool because Oven can be designed on the web but applications cannot be designed directly on Mac or Windows. The Balsamiq tool will help you understand the task process of UI work and highlight the benefits of digital prototyping to test the execution of expected results in a fast fashion compared to high-level prototyping. We also present the outcome of this work through two case studies. In particular, the smart mirror project with voice recognition function shows the effectiveness of the proposed method as an example.

• Journal of the Optical Society of Korea
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• v.19 no.6
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• pp.629-637
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• 2015

Compact system cameras (CSCs) are commonly used nowadays and feature enhanced video functions and thin yet light interchangeable lenses. They differ from digital single-lens reflex (DSLR) cameras in their lack of mirror boxes. CSCs, however, have autofocus (AF) speeds lower than those of conventional DSLRs, requiring weight reduction of their AF groups. To ensure the marketability of large telephoto zoom lenses with fixed f/2.8 regardless of field angle variation, in particular, light weight AF groups are essential. In this paper, we introduce a paraxial optical design method and present a new, large, telephoto zoom lens with f/2.8 regardless of the field angle variation, plus a lightweight AF group consisting of only one lens. Using the basic paraxial optical design and optimization methods, we fabricated a new and lighter zoom lens system, including a single-lens, lightweight AF group with almost the same performance.

• Journal of the Optical Society of Korea
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• v.13 no.2
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• pp.251-255
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• 2009

In the non-contact 3-dimensional (3D) shape measurements, the fringe pattern projection method based on the phase-shifting technique has been considered very effective for its high speed and accuracy. The digital fringe projector in particular has great flexibility in generating fringe patterns since the patterns can be controlled easily by the computer program. In this work, we have developed a high-speed digital laser grating projection system using a laser diode and a polygon mirror, and evaluated its performance. It has been demonstrated that all the optical measurements required to find out the profile of a 3D object could be carried out within 31 ms, which confirmed the validity of our 3D measurement system. The result implies the more important fact that the speed in 3D measurement can be enhanced remarkably since, in our novel system, there is no device like a LCD or DMD whose response time limits the measurement speed.