• KIEAE Journal
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• v.7 no.5
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• pp.29-34
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• 2007

Discomfort glare from windows is an important issue in window and daylighting design. This study aims to investigate the effect of luminance difference between the lower and the upper part of a large glare source. Experiments were conducted using a luminous body divided into two parts, the upper part and the lower part. The degree of discomfort glare from the luminous body was examined. The result shows that the part with lower luminance is perceived as a glare source when the part has higher luminance then the background luminance. The degree of discomfort glare was estimated for the experimental conditions, and compared to the observations. The estimation was made using two methods: one summed the glare sensation for each section, and the other used the average luminance of the whole luminous body. The result of the comparison shows that the method using the average luminance has approximate values to the observations. Consequently, the use of the average luminance was proposed for evaluation of discomfort glare from non-uniform large glare sources.

• International Journal of Highway Engineering
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• v.17 no.1
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• pp.129-142
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• 2015

PURPOSES : The purpose of this study is to suggest a basis for setting appropriate safety goals specifically related to the threshold zone luminance in a vehicular traffic tunnel. METHODS : In the test, drivers were divided into two groups. One group consisted of all drivers (average drivers) group with an age ratio of drivers holding domestic driver's license and driver group by age to produce threshold zone luminance in the tunnel. The threshold zone luminance produced as a result was used to analyze how it affects the safety level of each driver group and provide a basis for setting an appropriate safety criterion that can be used to determine threshold zone luminance. We used test equipment, test conditions, and ananalysis of threshold zone luminance identical to that reported by ChoandJung(2014) but the values of adaptation luminance in our analys is were expanded to range from100 to $10,000cd/m^2$. RESULTS : Adaptation luminance and threshold zone luminance are found to be related by a quadratic function. The threshold zone luminance needed by older drivers to ensure a certain safety level is significantly higher than that for drivers of other age brackets when adaptation luminance increases. 56% of older drivers are at an increased risk of an accident at the same luminance for which the safety level of average drivers is 75%. The safety level that can be achieved for older drivers increases to above 60% when threshold zone luminance level is set with the goal of attaining a safety level of more than 85% for average drivers. The safety level that can be attained for average drivers is above 90% when the threshold zone luminance is high enough to ensure over 75% in the safety level of older drivers. Results of this study are applicable to highways and others whose designed speed is 100 km/h. CONCLUSIONS : Threshold zone luminance determined on the basis of drivers having average visual ability is of limited value as a performance standard for ensuring the safety of older drivers. Hence, safety level for older drivers should be considered separately from safety levels for drivers with an average ability to avoid risk. Upward adjustment of older drivers' safety level in the process of determining appropriate threshold zone luminance in a vehicular traffic tunnel may bring both tangible and intangible benefit as a result of reducing accidents. However, there is an associated dollar cost arising from installing and operating lights. As a result, the economic impact of these trade-offs should also be considered.

• The Proceedings of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.2
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• pp.133-133
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• 1999

Average illuminance and luminance can be calculated by graphical methods to a certain extent but to calculate for a wide place a suitable software is needed. Softwares suitable for this purpose have been already developed in foreign nations, but the appropriate softwares for domestic use have not been developed. Therefore a program is developed which is executable in Hangul Windows. The softwares LAPRoad, is developed to calculate luminance and illuminance distribution of road surface, as well as average luminance and illuminance, overall uniformity, longitudinal uniformity, threshold increment veilling luminance and glare. And an apparatus that measures road surface reflection properties is developed. Because the road surface reflection properties is very important in luminance calculation, then concrete road surface reflection properties were measured.

• Journal of the Optical Society of Korea
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• v.18 no.1
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• pp.89-94
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• 2014

It is established that the perceived image contrast is affected by surround luminance. In order to get the same perceived image contrast, the optimum surround compensation ratios for those surround conditions is needed. Much research has been performed for dark, dim, and average surrounds. In this study, a wide range of surround luminance from dark up to $2087cd/m^2$ was considered. Using magnitude estimation method, the change in perceived brightness of six test stimuli was measured under seven surround conditions; dark, dim, 2 levels of average, bright, and 2 levels of over-bright surrounds. To drive the perceived image contrast from the perceived brightness, two different definitions of contrast were tested. Their calculated results were compared with the visual data of our previous work. And to conclude, the perceived contrast compensation ratios were 1:1.11:1.2 for average, dim and dark surrounds. These were close to CIECAM02 model (1:1.17:1.31). Besides, for average, bright, over-bright1 and over-bright2 surrounds the ratios 1:1.17:1.42:1.69 were determined. For intermediate or more extreme surround conditions, the compensation ratio was obtained from the linear interpolation or extrapolation.

• KIEAE Journal
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• v.9 no.6
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• pp.65-72
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• 2009

Lighting for outdoor advertising is very common feature of building facades as they provide the information and commercial identification. As the interest of improving street beautification more widely, application of various lighting technologies has been develop for advertisement such as electric sign board and signage. Furthermore, the installation of higher sign luminance than needed has many negative consequences, including higher energy consumption and light pollution. There are now no standard for outdoor advertisements in terms of luminance, and installation of indiscreet outdoor advertisement without luminance consideration is becoming more commonplace. This study was to evaluate the luminous characteristics of outdoor advertising as a function of sign and building facade luminance, luminance ratio. Data were collected on 8 electric sign boards, 20 internally illuminated, externally illuminated, neon, and channel letter signs and 4 commercial areas. Photometric measurements were taken by CS-100(Minolta) and ProMetric-1400(Radiant Imaging) for various sign modes and sign design. Also luminance of building facades were analyzed according with CIE standard of maximum obtrusive light permitted for exterior lighting installations. The findings are as follows; (1) There were excessive luminance of electric sign boards that could affect adjacent building facade and night sky luminance. (2) Sings that are externally illuminated providing an inappropriate amount of light on to the outer surface of the sign caused higher building facade luminance and potential of unnecessary glare.

• Journal of Korean Ophthalmic Optics Society
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• v.5 no.1
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• pp.43-48
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• 2000

It was to adjust the luminance of light by the rotation angle of the polarizes and analyzer. The luminance value Lmax, Lmin of Contrast Sensitivity could be obtained from the rotation angle ${\theta}_m$ of the average luminance($L_m$), the rotation angle(${\theta}_{max}$, ${\theta}_{min}$) of the maximum and the minimum's amplitude. $$L_{max}=I(0)e^{-2at}{\cdot}cos^2{\theta}_m(1+C_s^{-1})$$ $$L_{min}=I(0)e^{-2at}{\cdot}cos^2{\theta}_m(1-C_s^{-1})$$ We obtained the rotation angle(${\theta}_{max}$, ${\theta}_{min}$) of the polarizes and analyzer from the rotation angle ${\theta}_m$ of the average luminance($L_m$) and the Contrast Sensitivity($C_s$). $${\theta}_{max}=cos^{-1}[cos{\theta}_m{\cdot}(1+C_s^{-1})^{1/2}]$$ $${\theta}_{min}=cos^{-1}[cos{\theta}_m{\cdot}(1-C_s^{-1})^{1/2}]$$.

• Proceedings of the KIEE Conference
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• 2005.05a
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• pp.179-181
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• 2005

There is asymmetric in horizontal and vertical side of PDP cell. Every vertical line has BM(Black Mask) to improve luminance contrast. When error diffusion is processed in PDP system, these problems make an error bigger. In 4 inch PDP system, every red, green, blue color of test pattern is presented and each luminance is measured. That is called horizontal(H), diagonal right(R), diagonal left(L) and vertical(V). In red channel, high luminance descending order is V-H-R-L. In green channel, V-H-L-R. In blue channel, V-M-R=L. After average luminance of each direction is calculated. new weighted error diffusion(Weighted ED) is proposed. In digital image signal processing, the error in weighted ED is differ from ED's. The image of weighted ED is more less error compare to conventional ED and close to original image. As the gray level linearity and big size panel is adopted, weighted ED could produce good image.

• IEMEK Journal of Embedded Systems and Applications
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• v.13 no.6
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• pp.313-319
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• 2018

We propose a post-processing algorithm to improve the quality of the RGB image generated by deep learning based colorization from the gray-scale image of an infrared camera. Wavelet fusion is used to generate a new luminance component of the RGB image luminance component from the deep learning model and the luminance component of the infrared camera. PSNR is increased for all experimental images by applying the proposed algorithm to RGB images generated by two deep learning models of SegNet and DCGAN. For the SegNet model, the average PSNR is improved by 1.3906dB at level 1 of the Haar wavelet method. For the DCGAN model, PSNR is improved 0.0759dB on the average at level 5 of the Daubechies wavelet method. It is also confirmed that the edge components are emphasized by the post-processing and the visibility is improved.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.13 no.2
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• pp.1-6
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• 1999

Average illuminaoce and luminance can be calculated by grarhical rrethods to a certain extent, but to calculate for a wide place, a suitable software is needed. Softwares suitable for this purpose have been already developed in foreign nations, but the appropiate softwares for domestic use have not been developed 1berefore a program is develqJed which is executable in Hangul Windows. The softwares LAPRoad, is develqJed to calculate luminaoce and illuminance distribution of road surlace, as well as average luminance and illuminance, overall uniformity, longitudinal uniformity, threshold increement, veilling luminance, and glare. And an apparatus that measures road surface reflection properties is developed. Because the road surlace reflection properties is very important in luminance calculation, then concrete road surlace reflection properties were measered.asered.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.9
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• pp.1-7
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• 2008

This study is intended to compare physical properties of fluorescent luminaires with ones of LED luminaires so as to analyze fundamental characteristics of LED luminaires. For this, a comparative analysis of uniformity ratio of illuminance and luminance distribution of these two luminaires was made, and materials for applying LED luminaires to interior construction space were prepared. This study was carried out in four stages. First, a theoretical review on LED illumination light source was made compared with the existing luminaires. Second, a mock-up to control experimental variables to meet the objective of this study was manufactured. Third uniformity ratio of illuminance and luminance distribution of each luminaire were measured by using the mock-up. Fourth, a comparative analysis of uniformity ratio of illuminance and characteristics of luminance distribution of the existing fluorescent luminaires and LED ones was made. As a result of the study, the uniformity ratio of illuminance of LED luminaires, 0.559, was higher than one of the existing fluorescent luminaires, 0.522. Namely, it was shown that illuminance distribution of LED luminaires was uniform and global diffuse was good. As a result of measuring luminance distribution, it was found that luminance distribution of LED luminaires was more uniform than one of the existing fluorescent luminaires. The maximum luminance of fluorescent luminaires and LED luminaires over the wall was $180.6[cd/m^2]$ and $155.26[cd/m^2]$ respectively. Namely, the maximum luminance of fluorescent luminaires was higher than one of LED luminaires. The average luminance of fluorescent luminaires and LED luminaires was $44.32[cd/m^2]$ and $58.65[cd/m^2]$. Like this, the average luminance of LED luminaires was higher than one of fluorescent luminaires. Considering these results, it's thought that LED luminaires can give a person in the room a more comfortable working environment than fluorescent luminaires.