• Title, Summary, Keyword: Color Temperature

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Color Temperature Conversion Method Using Reference White Region Estimation

  • Do, Hyun-Chul;Chien, Sung-Il;Tae, Heung-Sik
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.872-875
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    • 2002
  • This paper presents an efficient method of estimating the correlated color temperature of an input color image and of generating a converted color image that can approximate the new target color temperature. After extracting the potential reference white region for an uncalibrated color image and estimating its correlated color temperature, the color conversion method produces a new color image with a target color temperature. Speed improvement and memory reduction have been achieved by using a simple transfer method without involving the CIE XYZ conversion step.

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Changes of Behavioral and Physiological Responses Caused by Color Temperature

  • Lee, Young-Chang;Min, Yoon-Ki;Min, Byung-Chan;Kim, Boseong
    • Science of Emotion and Sensibility
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    • v.18 no.2
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    • pp.37-44
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    • 2015
  • LED lighting has an advantage of adjusting color temperature. This change of color temperature may derive change in behavioral and physiological responses of the visual perception for indoor environments. This research examined the changes of behavioral and physiological responses caused by the color temperature. The environment was configured that the indoor temperature was 20 degrees centigrade or less as the perceived uncomfortable environment in winter. Then, the comfortable sensation vote (CSV) and the results of 3-back working memory test were measured as behavioral responses. In addition, the Electrodermal Activity (EDA) and Electrocardiogram (ECG) were measured as the responses of autonomics nervous system (ANS) in the three conditions of color temperature (red: 3862K, white: 5052K, blue: 11,460K). As a result, behavioral responses were not significant by the condition of color temperature, but the tendency of occupants' physiological relaxation appeared in the blue color temperature condition compared with the white color temperature condition. Although the color temperature of LED lighting might be a small factor in terms of the characteristics of indoor environment, it suggests that the color temperature could have an impact on the physiological changes in the parasympathetic nervous system.

Algorithm for Judging Anomalies Using Sliding Window to Reproduce the Color Temperature Cycle of Natural Light (자연광의 색온도 주기 재현을 위한 슬라이딩 윈도우 기반 이상치 판정 알고리즘)

  • Jeon, Geon Woo;Oh, Seung Taek;Lim, Jae Hyun
    • Journal of Korea Multimedia Society
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    • v.24 no.1
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    • pp.30-39
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    • 2021
  • Research in the field of health lighting has continued to advance to reproduce the color temperature of natural light which periodically changes. However, most of this research could only reproduce a uniform circadian color temperature of natural light, therefore failing to realize the characteristics of the circadian cycle of color temperature difference by latitude and longitude. To reproduce the color temperature of natural light on which the characteristics of a region are reflected, the collection technology of real-time characteristics of natural light is needed. If the color temperatures which are not within a periodical pattern due to climate changes, etc., are measured, it will be difficult to judge the occurrence (presence) of the anomalies and to reproduce the circadian cycle of the color temperature of natural light. Therefore, this study proposes an algorithm for judging the anomalies in real time based on the sliding window to reproduce the color temperature of natural light. First, the natural light characteristics DB collected through the on-site measurement were analyzed, the differential values at a one-minute interval were calculated and examined, and then representative color temperature circadian patterns by solar terms were drawn. The anomalies were then detected by the application of the sliding window that calculated the deviation of the color temperature for the measured color temperature data set, which was collected through RGB sensors, while moving along the time sequence. In addition, the presence of anomalies was verified through the comparison study between the detection results and the representative circadian cycle of the color temperature by solar term. The judgment method for the anomalies from the measured color temperature of natural light was proposed for the first time, confirming that the proposed method was capable of detecting the anomalies with an average accuracy of 94.6%.

Color Temperature Conversion of Uncalibrated Video Signal Based on Color Compensation in POP-TV

  • Do, Hyun-Chul;Chien, Sung-Il;Tae, Heung-Sik
    • 한국정보디스플레이학회:학술대회논문집
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    • pp.718-721
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    • 2003
  • It is often desirable that manufacturers and users can convert the reference white of display into the preferred color temperature by controlling the color temperature that is one of representative color characteristics of a light source. Accordingly, this paper proposes an efficient method of color compensation for displaying the uncalibrated video signal in PDP-TV and is also shown to be successfully coupled with flexible color temperature conversion based on the signal processing technique.

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Image Sensor Module for Detecting Spatial Color Temperature in Indoor Environment (실내 환경의 공간 색온도 검출을 위한 이미지센서 모듈)

  • Moon, Seong-Jae;Kim, Young-Woo;Lim, Yeong-Seog
    • The Journal of the Korea institute of electronic communication sciences
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    • v.16 no.1
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    • pp.191-196
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    • 2021
  • In this paper, we implemented an image sensor module possible of detecting color temperature in an indoor environment. The color temperature information in the video information acquired by the image sensor was matched with a color difference illuminometer to produce an LUT. An algorithm was developed so that color temperature information according to the received RGB values can be automatically calculated. As a result of measuring the color temperature with an image sensor indoors, an accurate result of less than 5.91% was obtained compared to the reference value. It was confirmed that the uniformity of 23.5% or more was excellent compared to the color temperature measurement result using a color sensor.

Effect of Color Developing by Water Treatment on Cotton Fabrics Dyed with Persimmon Extract (감물염색 면직물의 물에 의한 발색 효과)

  • Kim, Ok soo;Jang, Jeong dae
    • Fashion & Textile Research Journal
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    • v.19 no.5
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    • pp.646-652
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    • 2017
  • In order to clarify an availability of water treatment for persimmon extract dyeing, effect of color developing by water treatment process on cotton fabrics dyed with persimmon extract was investigated. Dyed fabrics were dipped still water and circulation water in various temperature. Concerning water color developing, still water color developing and circulation water color developing have been examined, and the temperature of water has been apprehended to prepare an effective basis of water color development. The surface color based on circulation water color development displays low values of $a^{\ast}$ and $b^{\ast}$, and the range of the c value(Munsell chroma) is narrow and has the value of 2 to 3, thus displays the coloration of a dark tone. The effect of temperature in water color development was insignificant, due to the small difference in temperature from $20^{\circ}C$ to $40^{\circ}C$. At $80^{\circ}C$, remarkable color development manifested, which is evidence of the high influence of temperature. The effects of circulation were clear at low temperatures, and the effects of temperature highly manifested at high temperatures. Circulation water color development display great color development at all temperatures to allow industrial color development with the absence of sunlight, thereby having an effect of energy reduction and developing color in dark tones, however this also is a strength of persimmon extract concerning color diversification, and is judged to have great value of industrial and practical application.

A Study on the Preference of Fluorescent Lamp and White LEDs by the Comparison of Color Temperature in a Office Space (사무공간에서 형광램프 조명기구와 백색 LED 조명기구의 색온도 비교를 통한 선호도에 관한 연구)

  • Jung, Yeon-Hong;Kim, Yu-Sin;Choi, An-Seop
    • Proceedings of the Korean Institute of IIIuminating and Electrical Installation Engineers Conference
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    • pp.3-6
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    • 2008
  • The purpose of this study is to investigate the luminous environment of fluorescent lamp and LED lamp in a office space for various color temperature by subject response test. For this, three different color temperatures were tested for the same illuminance level. Based on such test results for various color temperatures of fluorescent lamp and white LEDs, this study is to analyze the preferences of color temperature and light source, and perceptional brightness of each light source and color temperature. Then, this study is to derive the guidelines for the performance of color temperature which are suitable on the purpose and the mood of a office space.

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Electroencephalogram Analysis on Learning Factors during Relaxed or Concentrated Attention according to the Color Temperatures of LED Illuminance (이완집중 및 긴장집중 시 LED 조명의 색온도에 따른 학습요인의 뇌파분석)

  • Jee, Soon-Duk;Kim, Chae-Bogk
    • The Journal of Korean Institute of Educational Facilities
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    • v.21 no.6
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    • pp.33-42
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    • 2014
  • The objective of this study is to investigate learning factors (stability, attention and activation) in school by electroencephalogram (theta, alpha and beta waves) analysis during relaxed or concentrated. In order to measure electroencephalograms, MP 150 by Biopac and ECI Electro-Cap are employed. Three types of color temperatures (3000K, 5000K, 7000K) are used and 13 undergraduate and 12 graduate students are selected as experimental subjects. When subjects are relaxed during contemplation or concentrated during mental arithmetic, we compare with stability, attention and activation indices. The test results show that subjects were stable when color temperature is 5000K. Subjects gave best attention when color temperature is 7000K. Subjects activated well when color temperature is 3000K during relaxed attention. However, subjects activated rigorous when color temperature is 7000K during constrained attention.

Improvement of Color Temperature using Auxiliary Address Pulse Driving Scheme in 42-in. WVGA Plasma Display Panel

  • Park, Ki-Hyung;Lee, Eun-Cheol;Cho, Ki-Duck;Tae, Heung-Sik;Chien, Sung-Il
    • Journal of Information Display
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    • v.6 no.1
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    • pp.22-27
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    • 2005
  • Auxiliary address pulse driving scheme is proposed for controlling and improving the color temperature of the 42-inch WVGA ac-plasma display panel (ac-PDP) without sacrificing total luminance. Under a white-background, the color temperature of 42-inch ac-PDP is improved by about 1,700 K, whereas under a black-background, the color temperature of 42-inch ac-PDP is improved by about 3,200 K. In addition, by properly controlling the luminance in the R, G, and B cells, the color temperature of 42-inch ac-PDP can be raised from 5,827K to 10,705K.

Analysis on the Measured Electric Power Consumption of Dimmable LED Lamps for a Specific Illuminance and Color Temperature (색온도 구현방법에 따른 LED램프의 소비전력 측정 및 분석)

  • Jang, In-Hyun;Hong, Seong-Kwan;Choi, An-Seop
    • Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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    • v.25 no.2
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    • pp.24-31
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    • 2011
  • The purpose of this study is to find an efficient way using dimmable LED lamps to describe specific target illuminance and color temperature. This study used 14 dimmable LED lamps as same or different color temperature. The method of study is to measure of electric power consumption using different color temperature of dimmable LED lamps that were combination of two or three dimmable LED lamps by simultaneously dimming. Through this method, the electric power consumption was compared with all combinations of the illuminance and color temperature.