• Title/Summary/Keyword: low-light

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Detection of a Light Region Based on Intensity and Saturation and Traffic Light Discrimination by Model Verification (명도와 채도 기반의 점등영역 검출 및 모델 검증에 의한 교통신호등 판별)

  • Kim, Min-Ki
    • Journal of Korea Multimedia Society
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    • v.20 no.11
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    • pp.1729-1740
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    • 2017
  • This paper describes a vision-based method that effectively recognize a traffic light. The method consists of two steps of traffic light detection and discrimination. Many related studies have used color information to detect traffic light, but color information is not robust to the varying illumination environment. This paper proposes a new method of traffic light detection based on intensity and saturation. When a traffic light is turned on, the light region usually shows values with high saturation and high intensity. However, when the light region is oversaturated, the region shows values of low saturation and high intensity. So this study proposes a method to be able to detect a traffic light under these conditions. After detecting a traffic light, it estimates the size of the body region including the traffic light and extracts the body region. The body region is compared with five models which represent specific traffic signals, then the region is discriminated as one of the five models or rejected as none of them. Experimental results show the performance of traffic light detection reporting the precision of 97.2%, the recall of 95.8%, and correct recognition rate of 94.3%. These results shows that the proposed method is effective.

EXOSAT X-RAY LIGHT CURVES OF SS ARI

  • Kim, Yong-Gi
    • Journal of Astronomy and Space Sciences
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    • v.15 no.1
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    • pp.65-68
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    • 1998
  • We construct the X-ray light curves of the W UMa type contact binary SS Arietis(HD12929) from the EXOSAT data in HEASARC data archive. The phase dependent X-ray light curves obtained by using the ephimeris of Kaluzny & Pojmanski of SS Ari is modulated on the orbital phase as in the case of other W UMa type binaries. Although a detailed analysis of these data is impossible because of the very low X-ray light curves in the context of the radiation in the corona region of W UMa type stars.

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ULTRAVIOLET FLUX VARIATION OF EPSILON AURIGAE

  • Kang, Young-Woon
    • Journal of Astronomy and Space Sciences
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    • v.7 no.1
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    • pp.57-69
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    • 1990
  • The eighteen ultraviolet light curves of Epsilon Aurigae have been plotted using the integrated fluxes reduced from the 233 IUE low dispersion spectra taken between 1978 and 1986. The times of contacts and depth of eclipse have been determined from the light curves at the wavelength from 2550 $AA$ to 3050 $AA$. The UV light curves show two brightenings during the totality, the downward slope of the variation from the second to the third contacts, and asymmetry of the eclipse light curve. The two selected spectra note that the energy density distribution is not changed between the totality of the eclipse and out-of-eclipse.

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THE EFFECT OF LIGHT-CHILLING ON THE STRUCTURE OF PHOTOSYNTHETIC SYSTEMS IN CUCUMBER LEAVES

  • Eu, Young-Jae;Hwang, Hong-Jin;Lee, Choon-Hwan
    • Proceedings of the Korean Biophysical Society Conference
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    • 1996.07a
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    • pp.41-41
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    • 1996
  • Chilling-sensitive plants are damaged severly by chilling in the light. The activity of photosystem I(PSI) is known to be inhibited by low light-chilling and its iron-sulfur centers are presumed to be its primary target. In this report, the effect of chilling at 4$^{\circ}C$ in the light was investigated in the level of pigment-protein complexes in cucumber leaves compared with pea leaves. (omitted)

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High aspect ratio Zinc Oxide nanorods for amorphous silicon thin film solar cells

  • Kim, Yongjun;Kang, Junyoung;Jeon, Minhan;Kang, Jiyoon;Hussain, Shahzada Qamar;Khan, Shahbaz;Yi, Junsin
    • Proceedings of the Korean Vacuum Society Conference
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    • 2015.08a
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    • pp.235.2-235.2
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    • 2015
  • The front transparent conductive oxide (TCO) films must exhibit good transparency, low resistivity and excellent light scattering properties for high efficiency amorphous silicon (a-Si) thin film solar cells. The light trapping phenomenon is limited due to non-uniform and low aspect ratio of the textured glass [1]. We present the low cost electrochemically deposited uniform zinc oxide (ZnO) nanorods with various aspect ratios for a-Si thin film solar cells. Since the major drawback of the electrochemically deposited ZnO nanorods was the high sheet resistance and low transmittance that was overcome by depositing the RF magnetron sputtered AZO films as a seed layer with various thicknesses [2]. The length and diameters of the ZnO nanorods was controlled by varying the deposition conditions. The length of ZnO nanorods were varied from 400 nm to $2{\mu}m$ while diameter was kept higher than 200 nm to obtain different aspect ratios. The uniform ZnO nanorods showed higher haze ratio as compared to the commercially available FTO films. We also observed that the scattering in the longer wavelength region was favored for the high aspect ratio of ZnO nanorods and much higher aspect ratios degraded the light scattering phenomenon. Therefore, we proposed our low cost and uniform ZnO nanorods for the high efficiency of thin film solar cells.

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A Study of the Development of Lighting Equipment on Low Height Road Lighting (낮은 도로조명 방식의 기구디자인 개발연구)

  • Lee, Mi-Ae;Hwang, In-Tae;Kim, Hoon
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.23 no.8
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    • pp.1-7
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    • 2009
  • This study is intended to propose the environment friendly lighting which can be excluded the element of obtrusive light(glare, spill light) and to make the sight environment of the external and internal road more comfortable as newly approaching the lower positioned lighting from the current high pole lighting. Taking account of the current situation of putting the stress on the road sight scene. It is proposed the study focused on the aesthetic design for playing a role of scenery. For this, it is searched used situation of the low light at interior of the country and abroad and tried to find the improvement. Also it is tried find out how to raise the effectiveness. And throughout the site inspection and the data searching about the road facility of a road to be installed the low height lighting, it is suggested the standard of the lighting installation and the direction for the future on the light design and development of the low height lighting which is suitable for the domestic situation.

Adaptive Enhancement of Low-light Video Images Algorithm Based on Visual Perception (시각 감지 기반의 저조도 영상 이미지 적응 보상 증진 알고리즘)

  • Li Yuan;Byung-Won Min
    • Journal of Internet of Things and Convergence
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    • v.10 no.2
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    • pp.51-60
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    • 2024
  • Aiming at the problem of low contrast and difficult to recognize video images in low-light environment, we propose an adaptive contrast compensation enhancement algorithm based on human visual perception. First of all, the video image characteristic factors in low-light environment are extracted: AL (average luminance), ABWF (average bandwidth factor), and the mathematical model of human visual CRC(contrast resolution compensation) is established according to the difference of the original image's grayscale/chromaticity level, and the proportion of the three primary colors of the true color is compensated by the integral, respectively. Then, when the degree of compensation is lower than the bright vision precisely distinguishable difference, the compensation threshold is set to linearly compensate the bright vision to the full bandwidth. Finally, the automatic optimization model of the compensation ratio coefficient is established by combining the subjective image quality evaluation and the image characteristic factor. The experimental test results show that the video image adaptive enhancement algorithm has good enhancement effect, good real-time performance, can effectively mine the dark vision information, and can be widely used in different scenes.

IN VITRO PULP CHAMBER TEMPERATURE CHANGE DURING COMPOSITE RESIN CURING WITH VARIOUS LIGHT SOURCES (복합레진 중합 광원에 따른 치수강 온도 변화에 대한 생체외 연구)

  • Lee, Ji-Young;Kim, Dae-Eop;Lee, Kwang-Hee
    • Journal of the korean academy of Pediatric Dentistry
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    • v.31 no.1
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    • pp.85-91
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    • 2004
  • The purpose of this study was to observe in vitro pulp chamber temperature rise during composite resin polymerization with various light-curing sources. The kinds of light-curing sources were plasma arc light(P), low heat plasma arc light, traditional low intensity halogen light, low intensity LED(L-LED), and high intensity LED(H-LED). Temperature at the tip of light guide was measured by a digital thermometer using K-type thermocouple. Occlusal cavities$(2{\times}2{\times}1.5mm)$ were so prepared in extracted human premolars as to the remaining dentin thickness was 1mm. Dentin adhesive was applied to all cavities. Experimental groups consisted of no base group, ionomer glass base group, and calcium hydroxide base group. Temperature before and after resin filling was measured. Temperature at the light guide tip was the highest with P and the lowest L-LED. Temperature before resin filling was the highest with H-LED and the lowest with L-LED. Temperature after resin filling was the highest with H-LED and the lowest with L-P and with L-LED. The lining of base partially reduced the temperature rise.

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Low Voltage Driving White OLED with New Electron Transport Layer (New ETL 층에 의한 저전압 구동 백색 발광 OLED)

  • Moon, Dae-Gyu
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.22 no.3
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    • pp.252-256
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    • 2009
  • We have developed low driving voltage white organic light emitting diode with a new electron transport material, triphenylphosphine oxide ($Ph_{3}PO$). The white light emission was realized with a rubrene yellow dopant and blue-emitting DPVBi layer. The new electron transport layer results in a very high current density at low voltage, resulting in a reduction of driving voltage. The device with a new electron transport layer shows a brightness of $1150\;cd/m^2$ at a low driving voltage of 4.3 V.

Traffic Light Detection Method in Image Using Geometric Analysis Between Traffic Light and Vision Sensor (교통 신호등과 비전 센서의 위치 관계 분석을 통한 이미지에서 교통 신호등 검출 방법)

  • Choi, Changhwan;Yoo, Kook-Yeol;Park, Yongwan
    • IEMEK Journal of Embedded Systems and Applications
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    • v.10 no.2
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    • pp.101-108
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    • 2015
  • In this paper, a robust traffic light detection method is proposed by using vision sensor and DGPS(Difference Global Positioning System). The conventional vision-based detection methods are very sensitive to illumination change, for instance, low visibility at night time or highly reflection by bright light. To solve these limitations in visual sensor, DGPS is incorporated to determine the location and shape of traffic lights which are available from traffic light database. Furthermore the geometric relationship between traffic light and vision sensor is used to locate the traffic light in the image by using DGPS information. The empirical results show that the proposed method improves by 51% in detection rate for night time with marginal improvement in daytime environment.