• Journal of Korean Ophthalmic Optics Society
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• v.4 no.2
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• pp.65-71
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• 1999

The optical absorption spectrum was measured of the tinted powder, tinted solution and tinted lens in the visible regions. The tinted powder was very different with color of tinted lens that the optical absorptions was so higher, composed of the thick-gray color. The optical absorptions of tinted solution were just a little appeared by the energy split of a transition metal ion, so constructed with each color space. The optical absorptions of the tinted lens were appeared with the energy split peaks to a transition metal ion, so its were affected by the color constructions. The optical absorption peaks of each lens were depend on the tinted time. Blue color lens had a lot of absorption in the short wavelength regions than 500nm, and had a little appeared in the high wavelength regions than 500nm. In case of a yellow color, the optical absorptions were appeared quite contrary to the blue color, so these colors had the opponent-colors each other. In case of green color, the optical absorptions had a high in the both edges, had a low in the middle regions. In the pink color, by the optical absorptions form of quite contrary to the green color it, these colors had the opponent-colors each other. In the brown color, the optical absorptions had a maximum values in the short wavelength regions, and it gradually decreased goes by the long wavelength regions.

• Journal of The Korean Astronomical Society
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• v.53 no.6
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• pp.149-159
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• 2020

Gravitational lensing of point sources located inside the lens caustic is known to produce four images in a configuration closely related to the source position. We study this relation in the particular case of a sample of quadruply-imaged quasars observed by the Hubble Space Telescope. Strong correlations between the parameters defining the image configuration are revealed. The relation between the image configuration and the source position is studied. Some simple features of the selected data sample are exposed and commented upon. In particular, evidence is found for the selected sample to be biased in favor of large magnification systems. While having no direct impact on practical analyses of specific systems, our results have pedagogical value and deepen our understanding of the mechanism of gravitational lensing.

• Proceedings of the IEEK Conference
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• 2003.11a
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• pp.187-190
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• 2003

In this paper, we propose an extrinsic calibration method for a multi-view camera to get an optimal pose in 3D space. Conventional calibration algorithms do not guarantee the calibration accuracy at a mid/long distance because pixel errors increase as the distance between camera and pattern goes far. To compensate for the calibration errors, firstly, we apply the Tsai's algorithm to each lens so that we obtain initial extrinsic parameters Then, we estimate extrinsic parameters by using distance vectors obtained from structural cues of a multi-view camera. After we get the estimated extrinsic parameters of each lens, we carry out a non-linear optimization using the relationship between camera coordinate and world coordinate iteratively. The optimal camera parameters can be used in generating 3D panoramic virtual environment and supporting AR applications.

• Journal of The Korean Astronomical Society
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• v.47 no.6
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• pp.215-218
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• 2014

One-dimensional (1-D) microlens parallaxes can be combined with heliocentric lens-source relative proper motion measurements to derive the lens mass and distance, as suggested by Ghosh et al. (2004). Here I present the first mathematical anlysis of this procedure, which I show can be represented as a quadratic equation. Hence, it is formally subject to a two-fold degeneracy. I show that this degeneracy can be broken in many cases using the relatively crude 2-D parallax information that is often available for microlensing events. I also develop an explicit formula for the region of parameter space where it is more difficult to break this degeneracy. Although no mass/distance measurements have yet been made using this technique, it is likely to become quite common over the next decade.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.7 no.4
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• pp.17-23
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• 2008

Development of die technology for holder and barrel dies is necessary according to minimization of lens assembly, image sensor, and connectors. In these cases, there are two technical problems arising from die design. One is determination of knock-out pin location in die set. Minimization of lens assembly size make it difficult to obtain ejecting space. The other is whether or not high-precision die technology is possible to reduce torque variation when holer and barrel products is assembled. In this study, multi-cavity die set was developed taking advantage of gear-driven ejecting method. In the developed technology, die manufacturing technology was guaranteed with a high-precision level.

• Journal of Energy Engineering
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• v.26 no.1
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• pp.34-44
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• 2017

This paper deals with the effectiveness of a fiber optic solar lighting system that uses a Fresnel lens mounted on a two-axis solar tracker. A series of comparative analyses were made concerning its performance as compared to fluorescent lighting by using a simulation model based on ECOTECT and RADIANCE as well as referring to actual data. ECOTECT was used to model the test room (space) while RADIANCE was used for its indoor lighting conditions (environment). It was found that the average indoor light levels of fluorescent lighting fully satisfy the KS standard (KS A 3011, general office, class [G]: 300-400-600lux) whereas those of the solar lighting with light diffusers depends on the occlusion factor of roller shades installed on the south window.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.23 no.5
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• pp.131-138
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• 2023

In this paper, a free space optical communication device that can be used in a mobile base station of several km or less was fabricated and its characteristics were investigated. To overcome the loss due to atmospheric transmission, an optical fiber amplifier (EDFA) with an output of 23 dBm or more was used. In order to increase the focusing speed and miniaturization of the laser beam, an optical lens was manufactured, and a transmission lens was designed to have beam divergence within the range of 1.5 to 1.8 [mrad]. A PT module that controls PAN/TILT was fabricated in order to reduce pointing errors and effective automatic alignment between transceiver devices. In this study, Reed-Solomon (RS) code was used to maintain the transmission quality above a certain level. It was manufactured to be able to communicate at a wireless distance of 300m in a weather situation with visibility of 300m. For performance measurement, it was measured using BERT and eye pattern analyzer, and it was confirmed that BER can be maintained at 2.5Gbps.

• The Bulletin of The Korean Astronomical Society
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• v.39 no.2
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• pp.104.2-104.2
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• 2014

The RGB Bayer filter system consists of mosaic R, G, and B filters on the grid of photo sensors with which typical commercial DSLR (Digital Single Lens Reflex) cameras and CCD/CMOS cameras are taken. Many unique astronomical data taken with RGB Bayer filter systems are available, including transient objects, e.g., supernovae, variable stars, and solar system bodies. The utilization of such data in scientific research strongly requires reliable photometry transformation methods. In this work, we develop a series of formulae to derive magnitudes in the Johnson-Cousins BVR filter system from those in the RGB Bayer filter system.

• Korean Journal of Applied Biomechanics
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• v.13 no.1
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• pp.1-12
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• 2003

The purpose of this study was to design the method of 3D space calibration to reduce RMSE by statistical analysis when using the DLT algorithm and control frame. Control frame for 3D space calibration was consist of $1{\times}3{\times}2m$ and 162 contort points adhere to it. For calculate of 3D coordination used two methods about 2D coordination on image frame, 2D coordinate on each image frame and mean coordination. The methods of statistical analysis used one-way ANOVA and T-test. Significant level was ${\alpha}=.05$. The compose of methods for reduce RMSE were as follow. 1. Use the control frame composed of 24-44 control points arranged equally. 2. When photographing, locate control frame to center of image plane(image frame) o. use the lens of a few distortion. 3. When calculate of 3D coordination, use mean of 2D coordinate obtainable from all image frames.

• Journal of Korea Multimedia Society
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• v.24 no.4
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• pp.601-609
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• 2021

This article combines literature and empirical research based on space perception theory and the case study of mixed reality game "The Fragment." It is concluded that the mixed reality scene under space perception has a three-level visual definition. This definition carries out a corresponding level analysis of the scenes of the "The Fragment" game and draws up the constituent factors of the mixed reality game scene characteristics. Finally, through questionnaire data investigation and analysis, it is verified that the three factors of virtual reality coexistence, human-computer interaction, and local serviceability can better explain the characteristics of mixed reality game scenes. At the end of the study, it is concluded that the definition of three levels of visual hierarchy and the constituent factors of mixed reality game scenes can provide reference and help for other mixed-reality game designs and a brief description of future research plans.