• Current Optics and Photonics
• /
• 제6권2호
• /
• pp.161-170
• /
• 2022

Three-dimensional (3D) geometric models are introduced to correct vignetting, and a downhill simplex search is applied to determine the coefficients of a 3D model used in digital microscopy. Vignetting is nonuniform illuminance with a geometric regularity on a two-dimensional (2D) image plane, which allows the illuminance distribution to be estimated using 3D models. The 3D models are defined using generalized polynomials and arbitrary coefficients. Because the 3D models are nonlinear, their coefficients are determined using a simplex search. The cost function of the simplex search is defined to minimize the error between the 3D model and the reference image of a standard white board. The conventional and proposed methods for correcting the vignetting are used in experiments on four inspection systems based on machine vision and microscopy. The methods are investigated using various performance indices, including the coefficient of determination, the mean absolute error, and the uniformity after correction. The proposed method is intuitive and shows performance similar to the conventional approach, using a smaller number of coefficients.

• 조명전기설비학회논문지
• /
• 제27권9호
• /
• pp.1-5
• /
• 2013

We developed high-efficient 6W-LED package with simple structure by applying Heat Slug and silicone-reflector. LED package was manufactured in $8.5{\times}8.5mm$ sized multi-chip structure having thickness of $500{\mu}m$ achieved by bonding silicon-reflector with prepreg on top of the plate after implementing the reflector placed on copper substrate Half Etching by thickness of $200{\mu}m$. The luminous flux, luminous efficacy, correlated color temperature, color rendering index and thermal resistance of developed LED was evaluated, and it verified the application of products by applying it to 120W-LED road luminaires through simulation. The luminous efficacy of LED package reached over 130lm/W, and it is possible to be manufactured into 120W-LED road luminaires using 18 packages. In addition, the simulation results showed average of horizontal illuminance and overall illuminance uniformity that is suitable for three-lane road.

• 조명전기설비학회논문지
• /
• 제22권11호
• /
• pp.1-8
• /
• 2008

In this paper, the optical properties of the 54[W] LED module have confirmed by changing the angles of LED modules for street light applications. The angle of LED module changed from the $0[^{\circ}]$ to $60[^{\circ}]$ varying by $20[^{\circ}]$ as horizontal direction ${\ominus}_1$. Morever, the angle of LED module changed from the $0[^{\circ}]$ to $15[^{\circ}]$ varying by $5[^{\circ}]$ as vertical direction ${\ominus}_2$. As a result of simulation, the average illumination was about 17[lux] and the overall illuminance uniformity was 0.29 for a 10.39[m] long and 6[m] wide illuminance area at height of 6[m], which is acceptable for street lighting illumination in the Illuminating Engineering Society(IES) standard.

• 보존과학연구
• /
• 통권17호
• /
• pp.123-160
• /
• 1996

There have been many studies and experiments regarding exhibition lighting. Many experiments on photochemical damaging effect and visibility resulted in a practice limited to assigning light levels and adjusting annual exposure time. The three damaging factors to the artifacts are intrinsicsusceptibility to absorb radiant energy, spectral distribution of light source and intensity of illumination and time of exposure. Dividing all the artfacts into three categories to suggest a recommended illuminance level causes some problems. Blue wool, for example, used as the reference material for susceptibility, is not a standard material representing museum artifacts. In the most light sensitive category, ISO class I or anything below have been excluded. The exposure time of one soure can be three times more than another sourece. The spectral distribution of the light source and the relative spectral responsibility of the artifact are not considered in the practice. So in case of very light sensitive material, the recommended illuminance is only the referring value and it is indispensable to check the characteristic of susceptibility of each artifacts. Daylighting is prevailing method to solve the psychological need of the visitors. However, it sould transparent, and should not diffused, and the green-house effect must be considered. llluminance uniformity should based on the maximum illuminance to handle the limitation of exposure for the conservation of a large sensitive object such as a painting. Damage index is not absolute reference for selecting the lighting source because it is experimented from the paper of low grade then calculated. Visibility should be increased by reducing the visual noiseand by planning of appropriate luminance contrast. This paper reviews the problems with the previous studies and experiment sand the current exhibition lighting design practice. The plan for museum showcase lighting is to check the susceptibility and to raise the visibility simultaneously.

• 한국광학회지
• /
• 제23권2호
• /
• pp.55-63
• /
• 2012

본 논문에서는 광생물 반응기의 조명 시스템으로 활용될 LED(Light-Emitting Diode)용 도광판의 광학설계 및 제작 결과에 대해 보고한다. 도광판 설계를 위해 광원, 반사필름, 도광판 패턴에 대한 모델링을 수행하였다. 특히, 도광판 패턴의 경우 램버시안 산란체(Lambertian Scatterer)로 모델링을 수행하였는데, 테스트용으로 제작된 도광판의 조도분포와 부합하는 모델 파라미터(반사율, 산란체의 폭)를 매칭 시뮬레이션을 통하여 추출하였다. 추출된 모델 파라미터를 사용하여 광학설계를 수행하였으며, CNC(Computer Numerical Control) 가공을 통해 도광판을 제작하였고, 평균조도와 조도균일도 등의 광학 특성을 측정하였다.

• 한국태양에너지학회 논문집
• /
• 제32권3호
• /
• pp.104-113
• /
• 2012

A set of candela distribution curves(CDCs) were generated for a fiber optic dish daylighting system by Photopia under clear sky conditions at different solar altitudes. The candela distribution curves were then exported to Radiance for photometric analysis of a windowless lecture room. Observations were made on the Radiance rendered illuminance images, which provided photo realistic scenes varying with solar altitudes. If no tracking error were assumed, the daylight collection efficiency of the system remained at a constant value of 68.4% during its operation. Higher the solar altitude angle, greater in photometric quantities were observed, which are represented by candela(cd) and total lumens(lm). In all cases considered, however, the angle of light distribution remained fixed reflecting the solar tracking feature of the system. The illuminance uniformity on the workplane lingered around 0.12, which is quite low. This is quite a contrast to its average value of 0.68 of the $2.7m^2$ area directly below the terminal device (diffuser) of the system. The maximum illuminance of 1,340lux was obtained at a solar altitude of 80 degrees.

• 조명전기설비학회논문지
• /
• 제23권4호
• /
• pp.1-7
• /
• 2009

본 연구에서는 농촌 청소년 공부방을 대상으로 조명환경 실태조사를 실시하였다. 그 결과, 공부방의 평균 공간의 크기는 11.42[$m^2$]이며, 주로 광원은 형광등을 사용하였으며 조명사용방법은 전반조명만 이용하는 경우가 73.8[%]이며, 배광방식은 직접조명 방식을 주로 사용하고 있었다. 또한 스탠드를 소유하고 있는 가구는 45.7[%]이었으며, 국부조명인 스탠드를 사용하는 비율은 전체 조사대상의 20[%]에 지나지 않아 시작업이 효과적이지 못하였다. 내부공간 조도는 평균 131.82[lx]이며, 책상면 조도는 253.64[lx]로 최저허용조도의 42.3[%]에 해당하는 열악한 실정이었으며, 균제도는 평균 35.61[%]로 나타났다. 또한 사용자의 조명환경에 비해 만족도는 3.93점으로 높아 조명에 대한 인식이 매우 부족한 것으로 사료된다.

• 한국태양에너지학회 논문집
• /
• 제32권spc3호
• /
• pp.199-206
• /
• 2012

The purpose of this study is to understand the change of impression by comparing the uniformity lighting with the compound lighting. In previous study, we proposed a light controlling method to harmonize daylight from a window and artificial lights from a ceiling and obtained the results to support our method. We referred this method as the Adjusted Compound-Lighting Model (AC Model). The experiment is carried out with the scaled-models and mock-up spaces that were supposed to be an office space. One is lit by the uniform lighting and the other by the compound lighting in each experimental space. In order to present varying illuminance distributions, the two variables were used in this study. Subjects were asked to evaluate the point of difference by semantic differential rating on their overall impression after comparing with two rooms. The results showed that the impressions of compound lighting were more positive score than that of uniformity lighting on the items of 'dim-bright', 'dislike-like', 'artificial-natural' and 'closed-open', and that there was no significant difference in impressions between two spaces on other items.

• 한국광학회지
• /
• 제30권4호
• /
• pp.146-153
• /
• 2019

노광기는 회로 패턴을 원하는 위치에 전사시켜주는 장비로 패턴을 광학적 특성의 변형 없이 기재 상에 나타내기 위해서는 노광광학계의 특성이 매우 중요하다. 따라서 미세회로 패턴을 형성하기 위해서는 조사 면적에 작은 발산각으로 입사되어야 한다. 또한, 광원에서 나온 빛이 감광제와 균일하게 반응해야 하기 때문에 높은 광효율과 조도 균일도를 가져야 한다. 본 논문에서는 협각 구현의 문제점을 해결하기 위한 방법으로 반사형 타입인 파라볼라 반사경과 비구면 렌즈 설계를 진행하였고, 배열 후 시뮬레이션 분석 결과 광속 각도, 균일도, 최대조도가 목표 성능을 만족하는 것을 확인하였다.

• 한국주거학회논문집
• /
• 제1권2호
• /
• pp.91-101
• /
• 1990

The purpose of this study is to make use of the results, which have been obtained by field survey on the physical elements of daylight enviorment and by research on the subjective response of the students in classrooms, as fundamental data to improve the learning circumstances of classroom. This field survey was made for the students who are doing visual activities most of their time in a classroom formed by luminous environment. Two classrooms of H` Middle School are selected for this study. One is facing the south and the other is facing the east, The classfoom facing the southe was superior in daylight factor and illuminance, while both classrooms were poor in equality. Three factors(brightness, spaciousness, and glare) were drawn in the whole indoor visual environment and two factors(uniformity and reflection) were drawn in the warking plane environment.