Color classification of natural color images

The present article describes a color classification method that partitions a color image into a set of uniform color regions. The input image data are first mapped from device coordinates into the CIE L*a*b* color space, an approximately uniform perceptual color space. Colors used to represent a natural color image are classified by means of cluster detection in the uniform color space. The basic process of color classification is based on histogram analysis to detect color clusters sequentially. The principal components of a color distribution are extracted for effective discrimination of clusters. We present an algorithm for sequential detection of color clusters in the uniform color space, and the related algorithms for region processing and color computation. The performance of the method is discussed in an experiment using three kinds of natural color images.     

Color preference affected by mode of color appearance

Most color preference research focuses on colors in an object color mode. In our daily life, however, colors are perceived not only as an object color mode but also as other modes, such as unnatural object color and light source color modes. To explore the effect of the color appearance mode on color preference, we examined the relationship between color preference and the mode of color appearance. Thirty‐three color chips were chosen from the Munsell notation varying in hues and chromas. The color chips were presented in different color appearance modes by changing the subject's room illuminance and the color chip room illuminance. The experimental results showed that the brightest and most saturated colors were preferred. It was found that the subject preferred color in a light source color mode and unnatural object color mode to color in an object color mode. Moreover, we found that hue had a small effect on color preference in the light source color mode. We also investigated the relationship between color preference and the perceived color attributes (perceived chromaticness, whiteness, and blackness). In a supplementary experiment, elementary color naming was conducted. The results showed that the perceived chromaticness, perceived whiteness, and perceived blackness play a role for the determination of color preference for different color appearance modes. We, consequently, suggest that color preference is dominated not only by color attributes but also by the mode of color appearance. © 2009 Wiley Periodicals, Inc. Col Res Appl, 2010     

粘胶纺液着色用还原染料两元拼染中性色的研究

中性色具有特殊的色彩魅力,深受人们的喜爱.但是,因为中性色多为三次色,所以在印染加工中存在拼染困难、成品色光稳定性差等缺点,这对粘胶纺液着色加工,会产生致命的影响.本文选取8种还原染料,对以"两元拼色"方式拼染中性色的可行性进行了研究.实验表明,以"两元拼色"方式,基本可以实现对中性色的色调、饱和度和明度的覆盖."两元拼色"有利于提高中性色的拼染效率和成品色光的稳定性.     

An artist's preference for the pope color system

For the practice of painting and for teaching color theory the Pope color system has distinct advantages over other color systems. Within the Pope color solid all the visual attributes of color are clearly represented and can be visually displayed depending on where the solid is sliced. This helps clarify color terminology and facilitates understanding color relationships. It also has practical advantages for the artist who must have some knowledge of color both conceptually and visually in order to realize the possibilities of their arrangement in a painting.     

Product color emotional design considering color layout

Emotional experience and demand for product colors are important factors in users' decisions to buy and use a product. Therefore, accurately characterizing users' emotional responses of the product's color has become a significant consideration for product color design. However, a product color design problem exists in which it is challenging to accurately and efficiently position users' color image space because consumers have completely different image perceptions when encountering a large number of color schemes generated by different color spatial distributions. For this reason, this article proposes a product color emotional design method that considers the color layout. A table is built of an elemental composition for product color design, which contains color layout forms. This article also establishes a mapping model based on the semantic difference and back propagation neural network between the users' color image perceptions and the elements of the product's color design. The system recommends a color layout form that matches the users' emotional image goal through the k‐nearest neighbor algorithm, and then the form is initialized using a genetic algorithm. The system can realize the solution to the optimal product color scheme by optimizing and evaluating the population. Designers can make intuitive choices and decisions through the product color recommendation system. Through an example of color design for industrial vacuum cleaners, this article shows that the method has satisfactory feasibility and applicability for solving the problem of the optimization of product color design with color layout forms.     

A User‐Oriented Method for Preferential Color Scheme Generation

Harmony and preference are two important factors in constructing color combination for the purpose of color design. We presented a method for generating harmonious color scheme in a previous project. As an extension to the project, we propose here a method for generating color schemes that are based on user's preference. We considered color combinations as a set of color relations rather than a summation of specific color components (color elements); and we derived a model of six‐variable color relations, representative value of hue, representative value of saturation, representative value of lightness, span of hue, span of saturation, and span of lightness. With this model, color combinations can be expressed as specific parameters of the six‐variable model. Individual preferences are represented as certain parameters, from which new color schemes can be reconstructed to meet individual requirements. An interactive system for generating preferential color schemes is built with all these principles integrated. As a color design toolkit for user study, the system accesses user's preference features for color combinations, and provides new color schemes that fit the user's need. User study shows that both professionals and novices can generally acquire preferential color schemes of their own. © 2013 Wiley Periodicals, Inc. Col Res Appl, 40, 147–156, 2015     

Establishment of a color tolerance for yarn-dyed fabrics from different color-depth yarns

Yarn-dyed fabric is often woven from warp and weft yarns in the same color depth to ensure a uniform color appearance. The difference in color depth between warp and weft tends to result in the uneven color of the yarn-dyed fabric. This article aims to establish a color tolerance for yarn-dyed fabric that can be woven with a qualified color appearance but from the warp and weft yarns in different color depths. A total of 27 yarn-dyed fabric samples in three color series (red, yellow, and blue) were evaluated by using the yarn-dyed fabric from warp and weft yarns in the same color depth of 2% (on weight of fabric, owf) as the standard. Visual assessment and instrumental measurement of color were carried out to establish the color tolerance ellipse that was defined as CMC (Color Measurement Committee) color differences (2:1) of no more than 1.00. It was found that the color strengths (K/S) and color differences (ΔE_CMC(2:1)) of these fabric samples for each color series had linear relationships with the color depths of warp and weft yarns. The color tolerance ellipses indicated that, even though the warp and weft yarns had an apparent color difference, they could be woven in fabrics with relatively uniform color appearance and meet the requirements for yarn-dyed fabric. This work provided valuable insight into the production of qualified yarn-dyed fabrics from unqualified dyed yarns.     

彩色PVC异型材用色母粒颜料性能的研究

采用混合研磨法制备彩色PVC异型材用色母粒颜料。测试了不同载体对彩色PVC异型材相溶性及不同浓度对颜色的影响,通过CIE颜色测色系统对彩色PVC异型材外观颜色进行表征。结果表明:选用氯醋树脂作载体时,能同生产PVC异型材的原料聚氯乙烯树脂混溶,达到彩色PVC异型材外观色泽均匀。     

Color association research on red‐green dichromats in the color ergonomics of user interface interaction

With the development of our modern information society, digital products have become integrated into daily life. Research on the color ergonomics of user interfaces is a pressing issue. However, color‐vision‐deficient individuals (CVDIs), who account for 4.25% of the population, must use interfaces designed for individuals with normal color vision; the demands of CVDIs have not been sufficiently addressed. In this article, we investigate color associations in the color ergonomics of user interface interaction in a manner that aims both to improve interaction efficiency and to meet the psychological needs of CVDIs. First, we study color physiological cognitions in the color interactions of user interfaces for red‐green dichromats (RGDs) to determine the single‐color, two‐color, and three‐color combinations with high discrimination for a later experiment. Second, we explore the psychological–cognition relationships of colors in user‐interface interactions for RGDs. In an experiment involving 10 pairs of association semantemes and corresponding colors, the experimental results show that RGDs have different color cognitions caused by specific visual color expressions and unconscious environmental influences. Therefore, this article argues that RGD design should consider not only the habitual colors of solidified cognitions but also instinctive color associations. Finally, based on the results of previous experiments, we apply association color to the new interface design of computer security software (360 Total Security) for RGDs. Experimental results indicate that the application of color association in our new design can improve both interaction efficiency and CVDI user experience. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 547–563, 2016     

粉末涂料的颜色测控

介绍了粉末涂料的颜色测量与控制方法,包括颜色测量的基本知识、目测、仪器测量、配色及生产控制,详细介绍了仪器测配色流程,指出做好颜色测控工作必须把仪器测量与人的视觉评判、实践经验等充分结合起来。     

Color tolerance study on white in practical aspect: Perceptibility versus acceptability

This study investigates how the color tolerance for whites is affected by color category and context. Two experiments with different contexts, perceptibility or acceptability, were conducted using 27 color variation samples from six color categories (Neutral‐White, Red‐White, Yellow‐White, Green‐White, Blue‐White, and Blue‐Vivid). The results indicated that the color tolerance for Green‐white is dominantly higher relative to the other white‐based colors, whereas the color tolerance for Yellow‐White and Neutral‐White are relatively lower. However, contrary to the hypothesis, no significant differences in the level of color tolerances could be found between the two context of perceptibility and acceptability. The color tolerance thresholds for each color category groups in both experiments were similar. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 582–588, 2014     

Color matching experiment for highlighting interobserver variability

Human color vision differs from person to person, not only when color deficiencies occur but also within color‐normal populations. Investigating individual variability in normal color vision is beneficial both for clinical purposes and for quantifying observer metamerism. Researchers have used color matches such as Rayleigh matches, Moreland matches, the D&H color rule, and various combinations of different media for such investigations. However, none of them were originally aimed at investigating the interobserver variability in color‐normal populations, but rather were aimed at screening for color‐deficiencies. The objective of this study was, therefore, to design and carry out a color matching experiment where observer variability appeared as large as possible to detect the interobserver differences in the color‐normal population. Color matching was simulated under different combinations of reference spectrum and matching primaries using ColorChecker patches, different display/projector primaries, and the Stiles and Burch 49 observers. The simulation results showed: (1) The choice of spectra for the matching primaries had a significant effect on observer variability, (2) observer variability was large for near‐neutral reference colors, and (3) observer variability in the lightness direction was small relative to chromatic variability. The color matching experiment highlighting interobserver variability was designed based on these three findings and carried out for 61 color‐normal observers. Typical interobserver variability was 9.2 mean color difference from the mean (MCDM) using CIEDE2000 (spanning about 40 CIELAB units), which was much larger than any previous experiment. The obtained color matching data are useful for derivation, validation, and analysis of color matching functions. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 530–539, 2016     

Using symmetry to understand the attributes of color

The common attributes of color are distinguishable by their symmetries. Hue, saturation, chroma, chromaticness, whiteness, and blackness symmetries are discussed. Symmetries are generally not sufficient to specify unique formulas for color attributes, nor are they an endorsement of color model accuracy. However, symmetries do provide constraints for valid formulae, which are useful even when symmetries are only approximate. They also provide an alternate conceptual understanding of color attributes that differs from standard color science definitions. Symmetries provide a simplified framework for calculating groups of colors that share color attributes. Color models examined include the Hunt Model, a simple color model (SCM), various CIE color spaces, and IPT. A general functional form describes symmetries and scaling laws for many color models, and exceptions are discussed. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 27–44, 2008     

A comparison between wishes and status: Gray is not the preference for residents while the city shows neutral colors

Urban color has become one of the hot topics in China since 2000. To provide suggestions for making the urban color plan for Changzhou of about 253 square kilometers in 2011, the research group evaluated the visual quality of the present architectural color in real urban space and investigated the residential attitude for the present and the future ones. Open‐ended questionnaire of 1065 was taken effectively face to face accompanied with NCS Cascade 980 to understand the residents' attitude about the present architectural color in Changzhou city, and the expectations for the future. At the same time, an overall survey and evaluation on the present architectural color was conducted from the aspects of materials, functions, environmental and color relationship as well as the color code itself. Data reveal the residents' attitude to color preferences is more tolerant in hue with no special color bias, and inclined to those with obvious chroma and clear color predisposition, not very vivid, nor very dark. While the site survey shows the present color focuses mostly in high or middle‐high brightness, neutral ones. In site evaluation and analysis, architecture obtained good scores are those have obviously color predisposition. Colors that are inclined to good scores still have obvious color tendency but is lighter than that of good ones and mostly concentrate in the middle high and high brightness. Although still shows warm colors the most, the color tendency was not so obvious and the proportion of grayish ones increased. As to colors inclined to bad, very large proportion of grayish color existed. Actually, the most insurance color people usually thought, if has no good façade form supporting, is difficult to obtain a pleasant visual effect. Also, if the material is not in agreement with the color, the visual effect will be even worse.     

广告输出设备的颜色性能分析

围绕广告业彩色输出的硬件设备特性,通过建立的三维色域确定方法,探讨了常用广告输出设备颜色输出的物理能力。选择常用宽幅广告打印设备,针对广告色彩的常用输出模式,定量分析和比较了色域特征。结果表明,在广告行业中,针对一般的普通用户,目前市场上的Epson彩色喷绘设备具有相当的颜色输出效果;而对于高要求的专业级用户需求,则建议使用色域较大的喷绘设备,可获得一些黄、黄绿、绿,直至青颜色的高彩度色。     

Applying image‐based color palette for achieving high image quality of displays

In the highly competitive display market, manufacturers continuously develop new technologies to improve the image quality of displays. However, color measurement and visual assessment are time‐consuming to production lines. A new method to measure and improve color quality of the displays automatically therefore, is urgently needed to the manufacturers. This article proposes a familiar color correction strategy to optimize the colors of different displays by means of creating an image‐based color palette which enables color correction for familiar objects (e.g., facial skin, blue sky, or green grass) in the multidisplay systems. To produce the image‐based color palette, the 8‐bit RGB value of each pixel in an image is transformed to L*d*n* (lightness/dominant color/nondominant color) color channels, and the dominant‐color regions in an image are subsequently extracted from the dominant color (d*) channel. The memory color data of familiar objects can be set in reference monitor in advance to determine the dominant color (d*) channel. Then a series of palette colors are generated around a displayed image. The color palette will be displayed as a target for two‐dimensional colorimeter shooting to obtain the measured color data. The familiar color correction model was established based on a first‐order polynomial regression to achieve a polynomial fit between the measured color data and the reference color data on the color palette. The proposed method provides a solution to correct familiar colors on a displayed image, and maintains the original color gamut and tone characteristic in the multidisplay systems simultaneously. It is possible to achieve the preferred intent of the displayed images by using the proposed familiar color correction method. © 2012 Wiley Periodicals, Inc. Col Res Appl, 39, 154–168, 2014     

The impact of color preference on adolescent children's choice of furniture

It is widely believed that children will choose furniture that has the same color as their preferred color. Furthermore, for different categories of furniture, the color they preferred for furniture is consistent. A study of 508 adolescent Chinese children between the ages of 12 and 16 has been carried out to explore whether color preference influences their choice of furniture when they are provided with various color options (16 chromatic and five achromatic colors). This work tested six items of furniture in two functional spaces (study and bedroom space). Findings indicate that adolescent children's color preferences did indeed affect their furniture choice, but the extent varies with the categories of furniture. Furthermore, this study reveals that children's preference for furniture in different functional spaces is slightly different. Some effects of gender and age were also explored. This work discusses the implications of adolescent color preference and color choice for children's furniture color design.     

Categorized color space on CRT in the aperture and the surface color mode

The study was made for structure of categorized color space in the aperture and the surface color modes. The color appearances of two modes were reproduced on a CRT display with or without a surround configuration. Subjects made categorical color naming with 11 basic color terms. The (x,y,L) color space divided with these terms showed structural difference between the two modes. This result indicates that color is categorized by only chromaticity in the aperture color mode but by luminance and chromaticity in the surface color mode. © 1993 John Wiley & Sons, Inc.     

电脑测配色系统在实色涂料中的应用

简要介绍电脑测配色系统中的硬件和软件系统中的概念,详细阐述了应用于atacolor电脑测配色系统建立配色数据库的过程,及影响电脑测配色系统在实色涂料中颜色精度的因素。