• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.1
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• pp.17-23
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• 2008

In this paper, we used "Double Photometric System for Road Lighting" and measured roadway lighting of the metropolitan area by a measurement of illuminance and luminance. As a result, so many roads were dissatisfied with the permitted range of roadway lighting because of the road shape, lighting method, trees lining a street and obstacles.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.4
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• pp.25-35
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• 2017

This study aimed to analyze a driver's night visibility, according to the installation of a lighting system for driving an agricultural machine during the night time. For the night visibility analysis, a luminance measurement test on the lighting system and a gaze duration measurement test through eye movement measurement devices were carried out. In the luminance measurement test, the increase of luminance was confirmed as relative distance from an agricultural machine was closer and the conditions of the lighting equivalence are improved. Also the gaze duration measurement test, total gaze duration from an agricultural machine increased, as the conditions of the lighting equivalence are improved. In addition, it was identified that the difference in average gaze duration from an agricultural machine was statistically significant as the agricultural machine was driven in high speed. In conclusion, when the lighting system is installed on an agricultural machine, a driver's night visibility from the agricultural machine improves, which is expected to be enormously helpful to the prevention of agricultural machine accidents.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.29 no.4
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• pp.18-29
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• 2015

The purposes of this research and development are as follows: first, to provide pleasant driving environments inside tunnels; second, to improve the current illumination environments lacking in diffusion luminance meters to meet tunnel lighting standards; and, third, to reduce the consumption of tunnel lighting energy accounting for approximately 65% of tunnel maintenance costs because of inadequate visual environments and tunnel operations. Further details are listed below. Firstly, an image luminance meter for tunnels that can implement the L20-method which is a tunnel luminance method that follows the international standards of CIE88, which was developed in order to improve and change the existing illumination-based tunnel lighting operation system to a luminance-based system. (The margin of error of below 5% according to the results of a test by an authorized agency and field test). Secondly, early illumination control is possible since the lighting control system that can be operated based on luminance enables interlocking control of the inside and outside of a tunnel using ethernet communication. Thirdly, guidelines for field application of the system are proposed. In addition, the luminance inducers of tunnels are found and the reflexibility of each facility that may reduce luminance of the boundaries is also proposed. Fourthly, as a result of a test bed, power consumption of luminance-based lighting operations decreased by 15.6% compared to illumination-based operations. Applying the feedback controls and maintenance factors of internal/external luminance meters, it reduced by 36.4%. Therefore, we became able to provide a luminance-based lighting operation system that complies with tunnel lighting design standards and provides a visual environment for drivers.

• Proceedings of the KIEE Conference
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• 2004.07c
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• pp.1915-1917
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• 2004

Inductively coupled plasma is commonly used for electrodeless lamp due to its ease of plasma generation. Optical characteristics significantly depend on the RF power and gas pressure of the plasma. This paper describes the measurement of luminance as a function of RF power and gas pressure with a goal of finding optimal operating conditions of the electrodeless lamp. The gas pressure was varied from 10 [mTorr] to 500 [mTorr] and the RF power was varied from 10 [W] to 200 [W]. It was found that the luminance tends to be decreased when argon pressure is increased, and the luminance is increased as RF power is increased. It was also found that the luminance per unit RF power is high when the argon pressure is low and when the RF power is in the range of 30 [W]${\sim}$40 [W].

• Journal of the Optical Society of Korea
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• v.16 no.2
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• pp.145-150
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• 2012

We present a display-based visual stimulator for psychophysical and electrophysiological visual sensitivity measurements. The stimulator offers various psychophysical visual stimuli and transfers the signals from external devices along with the stimulation signals to an electrophysiological recorder. As an experimental demonstration, we perform a visual sensitivity experiment in the mesopic vision range by using the display-based stimulator. The intensity of the steady-state visual evoked potential is observed to correlate with the luminance of the flickering visual stimulation. For the psychophysically determined detection thresholds, we determine the mesopic luminance, showing agreement with the perceived brightness within the uncertainty of the luminance measurement.

• The Transactions of the Korean Institute of Electrical Engineers C
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• v.53 no.2
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• pp.91-96
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• 2004

In darkroom condition, it was observed that a white picture pattern lasted several minutes leaves a recognizable trace in subsequent black background picture. Although this is not a serious problem for the most current public display or home TV applications, the image sticking should be minimized for future high quality multimedia display applications. In order to characterize this picture memory effect having relatively long time scale, spatially resolved luminance measurement and light waveform measurement have been performed. Pixels located at the outer boundary of white pattern previously displayed shows highest luminance. These cells also shows fastest ignition at the ramp up reset sequence. The luminance and ignition voltage differences between boundary cells and the other cells are increased with display duration and number of sustain-pulse. It is speculated that image sticking observed at the boundary cell is originated from the transport of charged particles and re-deposition of reactive species such as Mg, O provided from strong sustain discharge region.

• Journal of Korean Tunnelling and Underground Space Association
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• v.17 no.1
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• pp.1-9
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• 2015

This paper introduces the development of imaging luminance meter which measures the luminances of external/internal road tunnel. The developed imaging luminance meter complies with both L20 method and Veiling luminance method of the international standards, CIE88. In this paper the L20 method is mainly presented because most of tunnels currently adapt L20 method. The developed system has an embedded computer to operate at stand-alone. The system has a ethernet port, a heater, a fan, a defroster, a wiper and sun shielder. Compensation algorithm is applied for correcting non-linear responses to the luminance and integration time. The accuracy of measurement is less than 1% when it calibrated at the public certification institute. The developed system was also tested at the real field, road tunnel. The test results were very similar with the reference luminance meter and showed that the developed system operates well at the real field. Partial sensor saturations were happened to show the less luminance, because there were the high reflecting objects in the real field. Further study should be followed for high luminance measurement.

• 한국정보디스플레이학회:학술대회논문집
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• 2005.07a
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• pp.259-262
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• 2005

Image retention is a kind of fatal shortcoming of the AC PDPs for realizing high-quality picture. In this work, the measurement method of image retention was proposed using temporal measurement of luminance, CIEXYZ tristimulus values, IR emission of reset pulse, and temperaturel. On the base of temporal measurement of luminance, CIEXYZ tristimulus value, and IR emission of reset pulse, the retention time of Ne+5%Xe gas-mixture discharge was about 2 hours after white window image. However, it was about 20 minute on the base of temporal measurement of temperature.

• 한국정보디스플레이학회:학술대회논문집
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• 2004.08a
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• pp.623-624
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• 2004

The coating and estimation of gas and moisture barriers on polymer and glass substrates are receiving very much attention in passivation of organic light emitting devices (OLEDs). In this study, the encapsulation and lifetime measurement techniques of OLEDs were presented. The degradation mechanisms of bare and encapsulated OLEDs were investigated by the visual lifetime measurement (VLM) system with the parameters such as a pixel luminance(L), a luminance rms roughness(dL), a brightness area ratio(R), an edge degradation depth(D), etc.

• Journal of Internet Computing and Services
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• v.16 no.2
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• pp.49-55
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• 2015

According to the statistics of traffic accidents over recent 5 years, traffic accidents during the night times happened more than the day times. There are various causes to occur traffic accidents and the one of the major causes is inappropriate or missing street lights that make driver's sight confused and causes the traffic accidents. In this paper, with smartphones, we designed and implemented a lane luminance measurement application which stores the information of driver's location, driving, and lane luminance into database in real time to figure out the inappropriate street light facilities and the area that does not have any street lights. This application is implemented under Native C/C++ environment using android NDK and it improves the operation speed than code written in Java or other languages. To measure the luminance of road, the input image with RGB color space is converted to image with YCbCr color space and Y value returns the luminance of road. The application detects the road lane and calculates the road lane luminance into the database sever. Also this application receives the road video image using smart phone's camera and improves the computational cost by allocating the ROI(Region of interest) of input images. The ROI of image is converted to Grayscale image and then applied the canny edge detector to extract the outline of lanes. After that, we applied hough line transform method to achieve the candidated lane group. The both sides of lane is selected by lane detection algorithm that utilizes the gradient of candidated lanes. When the both lanes of road are detected, we set up a triangle area with a height 20 pixels down from intersection of lanes and the luminance of road is estimated from this triangle area. Y value is calculated from the extracted each R, G, B value of pixels in the triangle. The average Y value of pixels is ranged between from 0 to 100 value to inform a luminance of road and each pixel values are represented with color between black and green. We store car location using smartphone's GPS sensor into the database server after analyzing the road lane video image with luminance of road about 60 meters ahead by wireless communication every 10 minutes. We expect that those collected road luminance information can warn drivers about safe driving or effectively improve the renovation plans of road luminance management.