• 대한전자공학회논문지SP
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• 제46권4호
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• pp.1-8
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• 2009

JPEG 및 JPEG2000과 같은 영상 압축 알고리즘은 고유의 손실 특성으로 인하여 영상 복원 시 화질을 열화시켜 색역(gamut)을 변화시킨다. 따라서 본 논문에서는 JPEG과 JPEG2000을 이용하여 압축률과 색역 변화의 관계를 연구하였다. 압축률과 색역 변화의 관계를 분석하기 위해 우선 표준 컬러 차트(Macbeth ColorChecker)의 18가지 색 표본을 이용하여 균일한 색 좌표계 내에서의 색상과 채도 변화를 조사하였다. 이를 근거로 12개의 자연 영상을 4가지 속성에 따라 2개의 그룹으로 분류하고 실험을 반복하였다. 그 결과 압축률과 색역 변화의 상관관계를 도출하고, 최소 자승법을 이용하여 근사화 곡선을 유도할 수 있었다.

• 한국방송∙미디어공학회:학술대회논문집
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• 한국방송공학회 2009년도 IWAIT
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• pp.80-84
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• 2009

This paper investigates the relationship between the compression ratio and the gamut area for a reconstructed image when using JPEG and JPEG2000. Eighteen color samples from the Macbeth ColorChecker are initially used to analyze the relationship between the compression ratio and the color bleeding phenomenon, i.e. the hue and chroma shifts in the a*b* color plane. In addition, twelve natural color images, divided into two groups depending on four color attributes, are also used to investigate the relationship between the compression ratio and the variation in the gamut area. For each image group, the gamut area for the reconstructed image shows an overall tendency to increase when increasing the compression ratio, similar to the experimental results with the Macbeth ColorChecker samples. However, with a high compression ratio, the gamut area decreases due to the mixture of adjacent colors, resulting in more grey.

• 한국의류학회지
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• 제44권1호
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• pp.68-83
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• 2020

This study suggests a method to predict the color appearance of textiles that shifts depending on illumination variations. The suggested method allows the calculations of lightness, chroma, and hue appearance values from the spectral reflectance values of the textile and illuminant. The accuracy of the method was evaluated through numerical and statistical comparisons between the predicted and the measured color appearance values of 24 fabric samples under CIE standard illuminant D65. As a result, there were excellent agreements between the two data sets with the error values close to zero. The predicted color appearance values of 24 samples under two illuminating (color temperature-luminance) conditions, 2700 K-100 cd/㎡ and 6500 K-100 cd/㎡, were then compared to prove the significant effect of illumination on the color appearance of textiles. The color appearance values were also compared with spectrophotometrically measured physical color attributes, that is, true colors of the samples. The physical color attributes of samples were unchanged; however, differences in color appearance under different conditions were generally much larger than the suprathreshold color difference tolerances discussed in the color science literature. Finally, the magnitude of the illumination effect depending on the physical color attributes of samples was also analyzed.