Papers by Keyword: Hue

Abstract: In this study, the color difference thresholds of the human eye for textiles in a wide range of colors under high-illuminance conditions were examined. As the high-illuminance conditions, 2856 K-2000 lux and 6504 K-2000 lux, which are in the range of illumination conditions used in spaces that highlight products such as show windows, were used. It was observed that people cannot generally perceive color differences in textiles smaller than 4.29 ΔE*_ab. Also, the color difference threshold varied depending on the color center and lightness of the textiles observed. Color differences in red and blue colored textiles were easier to be perceived than other colored textiles, while those in yellow colored textiles were the hardest to be perceived. It was also found that people are generally better able to discriminate colors between dark textiles than between light textiles. Meanwhile, the correlated color temperature of the illuminant, that is, whether it was a warm-white (2856 K) illuminant or a cool-white (6504 K) illuminant, did not significantly affect people’s perception of color differences in textiles under high illuminance conditions.

Abstract: Based on the current studies on visual comfort of stereo images, we studied the brightness, hue and saturation factors impact the comfort of stereo images combining the characters of human visual system (HVS) quantitatively. According to the improved limit method and subjective assessment experiments, we defined the comfortable matching and difference map of brightness, hue, saturation, and verified their universal applicability. The accurate rate can reach 90%.

Abstract: This paper proposes an improved color image enhancement algorithm based on 3-D color histogram equalization algorithm. When the existed 3-D color histogram equalization algorithms in the literatures are applied in processing dim color images, the processed color images often turn pale due to the decrease of color-saturations and have false contours due to gray-scale merging phenomenon in the histogram equalization algorithm. In this paper, the proposed algorithm can make more pixels of the processed color images keep their color-saturations and reduce the gray-scale merging with Logarithmic histogram equalization algorithm. Test results with dim color images present a better effect of image enhancement.

Abstract: A wood color grading method based on the characteristics of wood images and support vector machine(SVM). A high-performance color charge-coupled device camera captures color from wood samples and transmits images to the computer, then Hue from Munsell color system (HSI) and color vector angle (CVA) are used to characterize wood color of samples for the comparative purpose.These eigenvalues build two training sets,using support vector machine to establish the color classifiers,and test each classifier.The experimental results show that, the classification method based on the CVA and support vector machine can quickly and accurately estimate the level of the color of the wood materials, improve the level of automation and production efficiency in the wood processing.

Abstract: The fabrics made of different color values of Lightness (L), Chromaticity (C) and hue angle (h) of warp and weft silks were designed to testify color mixing. According to Glassman’s two-color adding and mixing principle, theoretical values of L0, C0 and h0 for all yarns were calculated. After all yarns were weaved, L1, C1 and h1’s value of each fabric were measured by ultrascan PRO of Optoelectronic integration color measurement instrument. The differences between measured and theoretical values expressed by ΔL, ΔC and Δh were calculated. ΔL, ΔC and Δh characteristics were analyzed and the relationship between ΔL, ΔC and Δh and the colors of warp and weft were discussed. The effects of the relative portion of warp and weft silks, the collection and distribution of interweave points, the uniformity of organized points’ distribution on color mixing based on the measured and theoretical values of fabric were further investigated.

Abstract: This study examined the application of color measurement to determining the chemical composition of Cu alloys such as Cu-Zn, Cu-Sn, and Cu-Al using a color recognition system. Measured data showed that the hue intensity changed exponentially when Zn, Sn, or Al in the Cu binary systems and fitted well with an exponential equation within the experimental error. This indicates that the obtained equations can be used for predicting the compositions of Cu-Zn, Cu-Sn, and Cu-Al systems by measuring the hue intensity.