• Title/Summary/Keyword: color contrast

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Color Image Enhancement Based on Color Constancy (칼라 항상성에 기초한 칼라영상 향상)

  • 배성호;김정엽;권갑현;하영호
    • Journal of the Korean Institute of Telematics and Electronics B
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    • v.30B no.5
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    • pp.103-108
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    • 1993
  • An image can be largely corrupted by the ambient illuminant, so that the image enhancement to restory natural color without respect to the ambient illuminant is needed. It this paper, a new color image enhancement technique based on color constancy is proposed. To enhance the image quality, higher volues of contrast and saturation are preferred, but their excessive values make an image unnatural. Since the color constancy processing preserves only hue, while reducing the dynamic range of lightness and saturation,the technique is needed in order to compensate this phenomenon. The proposed method transforms and increases lightness and saturation simultaneously to avoid the complexity in the related transformation by analyzing the relationship between the RGB and modified IHS coordinate system.

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Image Quality Enhancement Method using Retinex in HSV Color Space and Saturation Correction (HSV 컬러 공간에서의 레티넥스와 채도 보정을 이용한 화질 개선 기법)

  • Kang, Han-Sol;Ko, Yun-Ho
    • Journal of Korea Multimedia Society
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    • v.20 no.9
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    • pp.1481-1490
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    • 2017
  • This paper presents an image quality enhancement algorithm for dark image acquired under poor lighting condition. Various retinex algorithms which are human perception-based image processing methods were proposed to solve this problem. Although MSR(Multi-Scale Retinex) among these algorithm works well under most lighting condition, it shows color degradation because their separate nonlinear processing of RGB color channels. To compensate for the loss of the color, MSRCR(Multi-Scale Retinex with Color Restoration) was proposed. However, it requires high computational load and has additional parameters that need to be adjusted according to input image. In order to overcome this problem, a new retinex algorithm based on MSR is proposed in this paper. The proposed method consists of V channel MSR, saturation correction, and separate contrast enhancement process. Experimental results show that the subjective and objective image quality of the proposed method better than those of the conventional methods.

Changes of Contrast Sensitivity According to Light Transmittance of Color Lenses (색렌즈의 광투과율에 따른 대비감도 변화)

  • Lee, Sun-Haeng;Lee, Yoon-Jeong;Cho, Hyun-Gug
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.11
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    • pp.3427-3433
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    • 2009
  • This paper attempted to suggest the standards of light transmittance based on the analysis of the changes in contrast sensitivity of photopic condition according to the light transmittance of tinted lenses. The subjects of the experiment were 24 male and 13 female adults with normal ocular functions. They were asked to wear four tinted lenses (gray, brown, red, and green) in turn. The light transmittance of the lenses were 80~90%, 60~80%, 43~60%, and 30~43%, respectively. Contrast sensitivities were measured by using F.A.C.T. chart. The results showed that contrast sensitivities were decreased in proportion to the decrease of the light transmittance, and visual sensitivity of brown lenses were the highest and that of red lenses were the lowest. The results of the experiments suggested that the light transmittance should be over 38% for brown, gray and green lenses, and over 52% for red lenses. Accordingly the appropriate light transmittance should be considered when tinted lenses are selected for the purpose of eye protection in everyday life.

Smoke Detection Method Using Local Binary Pattern Variance in RGB Contrast Imag (RGB Contrast 영상에서의 Local Binary Pattern Variance를 이용한 연기검출 방법)

  • Kim, Jung Han;Bae, Sung-Ho
    • Journal of Korea Multimedia Society
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    • v.18 no.10
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    • pp.1197-1204
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    • 2015
  • Smoke detection plays an important role for the early detection of fire. In this paper, we suggest a newly developed method that generated LBPV(Local Binary Pattern Variance)s as special feature vectors from RGB contrast images can be applied to detect smoke using SVM(Support Vector Machine). The proposed method rearranges mean value of the block from each R, G, B channel and its intensity of the mean value. Additionally, it generates RGB contrast image which indicates each RGB channel’s contrast via smoke’s achromatic color. Uniform LBPV, Rotation-Invariance LBPV, Rotation-Invariance Uniform LBPV are applied to RGB Contrast images so that it could generate feature vector from the form of LBP. It helps to distinguish between smoke and non smoke area through SVM. Experimental results show that true positive detection rate is similar but false positive detection rate has been improved, although the proposed method reduced numbers of feature vector in half comparing with the existing method with LBP and LBPV.

A Study on the Evaluation Method of Perceptual Contrast with CIECAM02

  • Chong, Jong-Ho;Lee, Seung-Bae;Lee, Sang-Myung;Choi, Young-Chul;Bae, Jae-Woo;Kim, Hun-Soo;Chung, Ho-Kyoon
    • 한국정보디스플레이학회:학술대회논문집
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    • 2007.08b
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    • pp.1661-1663
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    • 2007
  • The contrast of display is one of the important specifications. Even if the contrast indicates luminance range which is a capability of the display and is greater in lower luminance or higher luminance, we consider that the greater contrast gets not the better performance. It is not the same value in human visual system. In practice, it is difficult to achieve the full dynamic range seen by human beings using electronic equipment. Therefore, we consider ambient condition and human perception to calculate perceptual contrast using the CIECAM02. In this paper, we propose perceptual contrast that is calculated using the brightness of CIECAM02.

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Luminance based transparency measurement for ice (조명 정보를 이용한 얼음의 투명도 측정)

  • Bae, Jungho;Park, Minchan;Lee, Jaekeun;Cha, Eui-young
    • Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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    • 2009.05a
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    • pp.419-421
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    • 2009
  • The freezing point would be different as the atmospheric pressure and humidity change. So if we can measure the transparency of ice, it should be easy that we approximate a freezing process and estimate the density of ice. This paper presents the method for estimating the transparency of ice in images. First, ice images are mapped to the $CIEL^*a^*b^*$ color space, and we make a new index for the ice transparency by using the average of $L^*$ and RMS(Root Mean Square) Contrast. In this case, the new index is better than the other existing method, i.e, Weber contrast, and Michelson contrast.

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Blind Quality Metric via Measurement of Contrast, Texture, and Colour in Night-Time Scenario

  • Xiao, Shuyan;Tao, Weige;Wang, Yu;Jiang, Ye;Qian, Minqian.
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.15 no.11
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    • pp.4043-4064
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    • 2021
  • Night-time image quality evaluation is an urgent requirement in visual inspection. The lighting environment of night-time results in low brightness, low contrast, loss of detailed information, and colour dissonance of image, which remains a daunting task of delicately evaluating the image quality at night. A new blind quality assessment metric is presented for realistic night-time scenario through a comprehensive consideration of contrast, texture, and colour in this article. To be specific, image blocks' color-gray-difference (CGD) histogram that represents contrast features is computed at first. Next, texture features that are measured by the mean subtracted contrast normalized (MSCN)-weighted local binary pattern (LBP) histogram are calculated. Then statistical features in Lαβ colour space are detected. Finally, the quality prediction model is conducted by the support vector regression (SVR) based on extracted contrast, texture, and colour features. Experiments conducted on NNID, CCRIQ, LIVE-CH, and CID2013 databases indicate that the proposed metric is superior to the compared BIQA metrics.

Modern Application of Design Elements on Ceremonial Costume of Korean Folk Belief (한국 민간신앙 의례복에 나타난 디자인 요소의 현대적 활용 - 배색을 중심으로 -)

  • Kim, Ji-Young
    • Journal of the Korean Society of Costume
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    • v.57 no.9
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    • pp.88-96
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    • 2007
  • The purpose of this study is to present examples for modern application with traditional color on ceremonial costume of Korean folk belief which is regarded as representative research material standing for Korean cultural archetype. The arrangements of color on the ceremonial costume of Korean folk belief were selected from 11 items specified as an import intangible cultural asset. These color arrangements were composed of fundamental colors from the viewpoint of modern color sensation, but had a excellent harmony in Hue. Therefore, not shifting Hue of color arrangement on ceremonial costume, traditional color arrangement was apply to contemporary it by shifting tone. Brilliant and deep chromatic tone that belong to 3, 4 area was converted into toned light grey, light clear, dark deep, toned dark grey, and greyish chromatic tone that belong to 1, 2 area or 5, 6, 0 area or 2, 7, 9 area. The plan that applies arrangement color with brightness contrast of traditional fundamental colors on a modern color harmony was presented from that. Like this, we can combine traditional color into modern color sensation, stylize and apply it on a production of character, logogram design, fashion design for characters in animation or game. From this, we'll be able to be close to the color arrangement sensation including our racial emotion in the everyday life.

A Study on Production of Optimum Profile Considered Color Rendering in Input Device (입력 장치에서 컬러 랜더링을 고려한 최적의 프로파일 제작에 관한 연구)

  • Koo, Chul-Whoi;Cho, Ga-Ram;Lee, Sung-Hyung
    • Journal of the Korean Graphic Arts Communication Society
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    • v.28 no.2
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    • pp.117-128
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    • 2010
  • Advancements in digital image have put high quality digital camera into the hands of many image professionals and consumers alike. High quality digital camera images consist originally of raw which have a set of color rendering operation applied to them to produce good images. With color rendering, the raw file was converted to Adobe RGB and sRGB color space. Also color rendering can incorporate factor such as white balance, contrast, saturation. Therefore, in this paper we conduct a study on production of optimum profile considered color rendering in digital camera. To do the experiment, the images were Digital ColorChecker SG target and ColorChecker DC target. A profiling tool was ProfileMaker 5.03. The results were analyzed by comparing in color gamut of $CIEL^*a^*b^*$ color space and calculating ${\Delta}E^*_{ab}$. Also results were analyzed in terms of different $CIEL^*a^*b^*$ color space quadrants based on lightness, chroma.

A Comparative Study of Color Emotion and Preference of Koreans and Chinese for Two-Color Combination by Naturally Dyed Fabrics with Persimmon and Indigo (감과 쪽의 천연염색 배색직물의 색채감성과 색채선호도에 대한 한국인과 중국인의 비교 연구)

  • Yi, Eunjou;Lee, Sang Hee;Choi, Jongmyoung
    • Journal of the Korean Society of Clothing and Textiles
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    • v.46 no.1
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    • pp.33-48
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    • 2022
  • This study was performed to compare the color emotion and preference of Koreans and Chinese for a two-color combination by dyeing cotton fabric with persimmon and indigo and to establish prediction models of color preference. Nine specimens prepared by combining two different colored fabrics (persimmon and indigo) were evaluated for color emotion and preference by Korean and Chinese groups of female college students. Koreans described most specimens as natural and traditional, whereas the Chinese described them as more pleasant and elegant as well as warmer and lighter than Koreans did. The contrast tone was the most preferred combination by both groups, whereas it was perceived as more modern and less warm by Koreans. Relationships between physical color variables and color emotions were quantified; these relationships were applied to establish a prediction model of color preference with tone combination types for each group. These results could help in making the design of fashion textiles more preference- and emotion-oriented for Korean and Chinese consumers.