• Proceedings of the Korean Printing Society Conference
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• 2000.04a
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• pp.35-44
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• 2000

Because Image on the CRT change under different illuminants, human is difficult to see original color of object. If what is information of used illuminant on capturing object know, image can be transformed according to viewing condition using the linear matrix method. To know information of used illuminant at an image, the spectral radiance of illuminant can be estimated using the linear model of Maloney and Wandell form an image. And then image can be properly transformed it using color appearance model. In this paper, we predict the spectral radiance of illuminant using spectral power distribution of specular light and using surface spectral reflectance at maximum gray area. and then we perform visual experiments for the corresponding color reproduction according to viewing condition. In results, we ensure that the spectral radiance of illuminant at an image can be well estimated using above algorithms and that human visual system is 70% adapted to the monitor's white point and 30% to ambient light when viewing softcopy images.

• Journal of Institute of Convergence Technology
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• v.3 no.2
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• pp.31-37
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• 2013

This paper proposes a vision-based inspection algorithm for a punch which is used when forming the head of the small screws. To maintain good quality of punch, the precise inspection of its dimension and the depth of the punch head is important. A CCD camera and an illumination dome light are used to measure its dimensions. And a structured line laser is also used to measure the depth of the punch head. Resolution and visible area depend on setup between laser and camera which is determined using CAD-based simulation. The proposed method is successfully evaluated using experiment on #2 punch.

• Transactions on Electrical and Electronic Materials
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• v.11 no.3
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• pp.138-144
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• 2010

Optical analysis is necessary to optimize light emitting diode (LED) safety street lighting. In this study, optical analysis was conducted for 100 W LED safety street lighting. Experimental research on such a single LED was the first undertaken. Simulation modeling based on the optical properties of the single LED has compared between average road illuminances and has them analyzed with Korean Industrial Standards for LED safety street lighting (KS C7658:2009). The simulation results demonstrated that the illumination performance (average road illuminance) was 75.3 lx at a height of 4 m and an area of $32\;m^2$, 45.25 lx at a height of 5 m and an area of $72\;m^2$, and 30.05 lx at a height of 6 m and an area of $128\;m^2$. 100 W safety street lighting (model CE180-ST-OS) designed by simulation was also compared between product and 100 W simulation modeling, and error rates averaged 5.6%. The 100 W LED safety street lighting base designed in simulation modeling was proven by comparison experiments. Through the simulations and the corresponding analysis, it was found that the tested 100 W LED safety street lamp had reasonable performance. The design method for LED safety street lamps has been summarized based on the optical analysis.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.37 no.2
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• pp.117-123
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• 2001

Anchovy scoop nets, a kind of lift net have been used in the coastal area of Cheju and South sea of Korea. An incandescent lamp(AC 100V, 1kW) is being used as a fishing lamp for gathering anchovy. Fishing lamp was installed at 1m ahead of the prow and 1.5m higher than the water surface. The fishing lamp let fish school rise to the water surface and attract to bag net. Accordingly, a successful anchovy catching depends on controling of fishing lamp. On the study, the distribution of spectral irradiance illumination of incandescent lamp(1kw) and the irradiance efficiency of reflection plate were analyzed and discussed to investigate the ability of fishing lamp which can attract anchovy school effectively. The results obtained are summarized as follows : 1. Around 180% of irradiance efficiency of incandescent lamp was increased by using the reflection plate. The light of lamp was radiated into water with circular shape. 2. The irradiance illumination of incandescent lamp in air was a maximum in wave length of 994nm but it was 690nm at 0.5m and 1.0m of water depth. 3. The relationship between water depth(x) and water illumination(y) of vertical light is represented as follows : y=146.03e supper(-0.37x) 4. The light of incandescent lamp(1kW) pass through much better into vertical direction than horizontal but it was estimated that the light was not able to reach depth of 20m.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.24 no.5
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• pp.427-431
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• 2011

Hybrid $SiO_2-TiO_2$ photoelectrode with different type of layers was investigated in dye-sensitized solar cells (DSSC). Use of a thin layer of nanocrystalline $TiO_2$ would imply reduction in the amount of dye coverage, however, lower amount of dye in the thin films would imply fewer electron generation upon illumination. So, thus, it becomes necessary to include a $SiO_2-TiO_2$ layer for increase light harvesting effect such that the lower photon conversion due to thin layer could be compensated. In this paper reports the use of transparent high surface area $TiO_2$ layer and an additional $SiO_2-TiO_2$ layer, thus ensuring adequate light harvesting in these devices. The best solar conversion efficiency 6.6% under AM 1.5 was attained with a multi-layer structure using $TiO_2$ layer/$SiO_2-TiO_2$ layer/$TiO_2$ layer for the light harvesting and this had resulted to about 44% increase in photocurrent density of dye-sensitized solar cells.

• Journal of the Korean Solar Energy Society
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• v.34 no.3
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• pp.66-74
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• 2014

In this paper, the performance of Hybrid Dimming control system for Daylighting system is evaluated by accredited tests. The system controls the balance of illuminance of daylight between daylight system and LED light system. It makes the normal illuminance of interior without the effects of weather by controlling the LED depending on the brightness of outside. For the tests, 6 diffusers($600{\times}300mm$) were installed in lighting area($36m^2$) and normal operation of the system sensors were tested about the interference of sunlight. The results of the examinations were satisfied with the criteria of accredited tests. Further research is the verification of energy saving effect by comparing the Hybrid Dimming control system to current artificial light system.

• Korean Journal of Heritage: History & Science
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• v.52 no.3
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• pp.188-199
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• 2019

In this study, research trends were investigated by examining important academic research on museum lighting that has been carried out in Korea over the past 30 years. The aim was to highlight important studies conducted in Korea on material deterioration caused by museum lighting and to examine the current status of research on LED light sources to provide direction for future research. The ultimate goal of studies on museum lighting is to improve the long-term conservation effects, and this study examined the latest light sources of each era. Prior to the 1990s, the effects of light sources on relics were assessed by investigating incandescent light bulbs and fluorescent lamps, the first museum exhibition lighting. Then in the 1990s, the introduction of halogen lamps and HID lamps led to the analysis of the characteristics of a light source itself and the introduction of illumination standards. In the 2000s, the lighting environment of museums was investigated based on the characteristics of the light sources that had been studied, and in terms of preservation, research was conducted not only to improve the conservation of relics but also to improve the sentiments of visitors. After 2010, LED lamps were introduced; therefore, material deterioration studies on LED lamps were expanded. During this period, enhancements to LED light sources were made, such as reducing the blue spike area and increasing color rendering. With the development of lighting used in museums and art galleries, the direction of the display preservation criteria has led to the need to prepare advanced standards, covering all aspects from the center of illumination to the consideration of the color of an object and the speed of radiation from the light source. Regular studies of museum lighting in a long-term perspective should be planned to standardize the more advanced conditions of material discoloration.

• Journal of Korea Society of Digital Industry and Information Management
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• v.17 no.1
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• pp.1-6
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• 2021

In this paper, to expand the use of standalone street lights, an algorithm for controlling LED energy consumption was proposed. The proposed method uses an LED module of a standalone street light divided into n zones. This is a method of reducing total power consumption by preventing the increase in power consumption due to high heat generation by weakly operating the entire LED according to the illuminance. When the amount of sunlight decreases, the whole LED operates weakly and then brightens, and unlike streetlight that act as streetlight, a method of dividing LEDs by area and limiting the number of LEDs operating according to illumination intensity was proposed. This is a way to use a lot of time with limited battery capacity by reducing the generation of heat that consumes the most power in streetlight. It is also a method of continuously changing the initial usage area to improve the total usage time of the LED substrate. As a result of the experiment, it was found that the proposed method extends the service time because it generates less heat than the conventional stand-alone streetlight.

• Proceedings of the Korea Society of Information Technology Applications Conference
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• 2005.11a
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• pp.65-68
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• 2005

In this paper, an algorithm to extract bar-space area is suggested. In a section of bar-code space area the threshold value is computed, and bar and space are extracted according to threshold value. PDF417 is used everyday life and printed in many different materials. The printed PDF417 is especially influenced by various light source. The decision of bar and space is very hard under the change of illumination. The fixed threshold value to distinguish the bar and space can not be applied. in these cases, The proposed algorithm is developed to investigate variable threshold. The variable threshold can be obtained by simple calculation.

• Korean Journal of Optics and Photonics
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• v.9 no.3
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• pp.205-211
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• 1998

The MTF(modulation transfer function) measuring system with a linear CCD(charge coupled-device) was constructed to cvaluate a color CRT(catode ray tube). The measured MTF values were corrected by considering the spectral response and the pixel sizes of CCD. The effects of a spot size, video bandwidth, pitch of shadow mask holes, display luminance, and ambient illumination on image quality were studied. The uniformity of resolution and the contrast Ioss by ambient light of the color CRT monitor were measured, and the results were analyzed by MTFA(modulation threshold area).