• The Journal of Korean Institute of Information Technology
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• v.16 no.11
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• pp.115-121
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• 2018

Fluorescent images using near-infrared light have no worry about radioactivity, and images can be checked in real time during surgery. Therefore experiments using fluorescent images for monitoring lymph node biopsy are actively under way. Fluorescent imaging equipment uses high heat-generating components such as LED and camera, thus uses water-cooling system as a stable heating suppression means. However in the fluorescent image equipment, the water cooling system takes a large volume which is a disadvantage in terms of miniaturization of the equipment. Even if the air cooling system is used for miniaturizing the equipment, heat generation is a problem. In this paper, we have experimented with the air cooling method using PWM control for the miniaturization of the equipment, and confirmed the constant quality of the fluorescent image and the suppression of the heat generation without any problems even when the equipment is used for a long time.

• Journal of the Semiconductor & Display Technology
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• v.19 no.4
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• pp.1-5
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• 2020

By adapting black body leadflame and thin film type Green A filter, we successfully demonstrated night vision imaging system (NVIS) Green A compatible LED. Fabricated NVIS compatible LEDs show small form factor compared to that of commercialized NVIS compatible LED. Especially, NVIS radiance and chromaticity of MIL-STD-3009 specification can be satisfied simultaneously and easily by controlling the color temperature of the white LED as well as the concentration of the Green A dye and the thickness of the Green A filter. The optimal dye concentration of the NVIS Green A filter is expected to be about 1 wt%. The results of this study are expected to contribute to miniaturization, weight reduction and localization of avionic display and lighting devices.

• Journal of Applied Biological Chemistry
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• v.64 no.3
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• pp.217-223
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• 2021

5-aminolevulinic acid (ALA) is a representative photosensitizer used in numerous fields including cancer diagnosis and treatment. In this study, experiments were conducted to optimize the growth of Rhodobacter sphaeroides and production of ALA through LED irradiation of various wavelengths, addition of organic acid precursors of ALA, and changes in glucose concentration. After 72 h cultivation, the 850 nm wavelength LED irradiated at the same light intensity as the incandescent lamp increased the growth of R. sphaeroides and the production of ALA about 1.5- and 1.8-fold as compared with the control, respectively (p <0.0001 and p <0.0001). As a result of culturing R. sphaeroides by irradiating an LED with a wavelength of 850 nm after adding organic acid to the final concentration of 5 mM in culture medium, the production of ALA was increased about 2.8-fold in medium supplemented with pyruvic acid compared with the control (p <0.0001). In addition, the growth of the strain and the production of ALA were increased about 2.9- and 3.4-fold in medium supplemented with 40 mM glucose compared to the control which added only 5 mM pyruvic acid, respectively (p <0.0001 and p <0.0001). The yield of ALA per cell dry mass was about 1.4 folds higher than that of the control in 20 and 40 mM glucose, respectively (p <0.001). In conclusion, the growth of R. sphaeroides and production of ALA were increased by 850 nm wavelength LED irradiation. It also optimized the growth of R. sphaeroides and production of ALA through organic acid addition and glucose concentration changes.

• Proceedings of the Korean Society For Composite Materials Conference
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• 1999.11a
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• pp.73-76
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• 1999

Near infrared spectroscopy techniques were used to study the cure reactions of epoxy resin system based on diglycidyl ether of bisphenol A(DGEBA) resins cured with 4, 4' diaminodiphenyl sulfone (DDS) hardner. Stoichiometric DGEBA/DDS resin formulation was involved in this study. The infrared absorption spectra of the prepared formulation were obtained on an FTIR spectrometer operating in the region of 11000 to 4000$cm^{-l}$. The chemical group peaks of interest in a DFEBA/DDS spectrum were identified by a comparative study with individual spectra of DGEBA and DDS monomers. Where necessary, special model compounds were used to identify unknown bands, such as the primary amine band at 4535$cm^{-l}$. The absorption bands of interest were integrated to quantify the areas and then converted to molar concentrations. This series of quantitative analyses of the major chemical groups led us to understand not only the reaction mechanism but also the cure kinetics. In this paper, the reaction mechanisms observed in stoichiometric DGEBA/DDS resin formulation and the various properties of the resin system as a function of cure temperature are described.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.64.2-64.2
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• 2012

The SPICA (SPace Infrared Telescope for Cosmology & Astrophysics) project is a next-generation infrared space telescope optimized for mid- and far-infrared observation with a cryogenically cooled 3m-class telescope. It will achieve the high resolution as well as the unprecedented sensitivity from mid to far-infrared range. The FPC (Focal Plane Camera) is a Korean-led near-infrared instrument as an international collaboration. The FPC-S and FPC-G are responsible for the scientific observation in the near-infrared and the fine guiding, respectively. The FPC-G will significantly reduce the alignement and random pointing error through the observation of guiding stars in the focal plane. We analyzed the pointing requirement from the focal plane instruments. The feasibility study was performed to achieve the requirements. Here, we present the role of SPICA/FPC as a fine guiding camera.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.10a
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• pp.126-128
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• 2008

본 연구에서는 포도송이를 절개하지 않고 광학적인 방법으로 당도를 측정하였다. 광원으로는 $615{\sim}635nm$ 파장 대역의 LED를 사용하였다. 포도의 당도는 안토시아닌의 분포량에 의해 결정되는데 적포도의 경우 적색이 강할수록 안토시아닌이 많이 분포되어있다. 측정 결과 적색을 많이 띠는 적포도의 경우 광 강도가 낮은 것을 확인하였다. 또한 광학적인 방법으로 측정된 광 강도와 당도계로 얻어진 당도를 비교 분석하였다. 그 결과 포도송이의 당도에 따른 상대적 광 강도를 확인하였다.

• Proceedings of The Korean Society of Agricultural and Forest Meteorology Conference
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• 2013.11a
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• pp.25-25
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• 2013

식생의 생물계절학적 특성은 지표면과 대기의 에너지와 물 순환에 큰 영향을 미친다. 일반적으로 상층군락과 하층군락의 식생은 미기후의 차이 등에 의해 서로 다른 생물계절학적 특성을 가진다. 이러한 식생의 생물계절학적 특성은 반사도 관측을 통해 추정할 수 있다. 과거부터 원격탐사 기법을 활용하여 식생의 생물계절학적 특성을 추정하는 많은 연구가 수행되어 왔다. 그러나 대부분의 연구는 상층군락과 하층군락의 반사특성을 구분하지 않았다. 본 연구에서는 상층군락과 하층군락 식생의 생물계절학적 특성을 구분하여 탐지하기 위해 red, green, blue 그리고 near-infrared 의 네 가지 파장대를 가진 LED 센서를 이용하였다. LED 센서는 광릉 시험림 내의 활엽수림과 침엽수림 관측지에 서로 다른 네 군데의 높이에 설치되어 각 파장대의 반사도를 산출하였다. 또한 반사도를 이용하여 세 가지 식생지수(NDVI, EVI, Greenness index)를 산출하여 상층식생과 하층식생의 개엽기를 추정하였다.

• Journal of the Optical Society of Korea
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• v.19 no.1
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• pp.102-111
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• 2015

This paper proposes an algorithm for recovering the colors of objects from multiple near-infrared (near-IR) images. The International Commission on Illumination (CIE) color coordinates of objects are recovered from a series of gray images captured under multiple spectral near-IR illuminations using polynomial regression. The feasibility of the proposed algorithm is tested experimentally by using 24 color patches of the Color Rendition Chart. The experimental apparatus is composed of a monochrome digital camera without an IR cut-off filter and a custom-designed LED illuminator emitting multiple spectral near-IR illuminations, with peak wavelengths near the red edge of the visible band, namely at 700, 740, 780, and 860 nm. The average color difference between the original and the recovered colors for all 24 patches was found to be 11.1. However, if some particular patches with high value are disregarded, the average color difference is reduced to 4.2, and this value is within the acceptability tolerance for complex image on the display.

• The Journal of the Korea institute of electronic communication sciences
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• v.19 no.1
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• pp.327-334
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• 2024

In this paper, we developed a system with a near-infrared LED light source with a wavelength of 950nm to acquire palm vein images and a white LED light source to acquire palm creases based on Raspberry Pi. In addition, we implemented a unique pattern-extractable image processing technology that can prevent counterfeiting and enhance security of mixed creases and palmprints through image pre-processing (Gray scaling, Histogram Equalization, Blurring, Thresholding, Thinning) for the acquired vein and palm images, and secured a source technology that can be used in a security-enhanced system.

• Journal of Convergence for Information Technology
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• v.12 no.5
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• pp.225-236
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• 2022

The purpose of this study is to provide clinical information and quantitative data through clinical research on lip balm containing propolis extract and lip application with LED device. Participants in this study were selected as test products for women aged 19 to 50 in Seoul and Gyeonggi Province, and to investigate the effects of LED devices and lip creams on the lips to improve lip elasticity, lip moisture, lip keratin, and lip moisture lasting for 12 hours. Before using the product, immediately after use, after 6 hours of use, after 12 hours of use, and after 2 weeks of use, the use test items are measured and the safety, efficacy, and preference survey of the product is analyzed. The results derived through a series of research procedures are as follows. It has been shown to help lip elasticity, lip moisture, lip keratin improvement, and lip moisture lasting for 12 hours when used once or 2 weeks.