Study of balance of images using visual weight

The purpose of this research is to analyze the factors that create a sensation of balance or unbalance when a color image is observed depending on the light transmitted, reflected, and/or emitted by the objects that appear in it. This study is carried out by calculating the center of gravity (CG) of each image. The weight and the CG are obtained by calculating the force resulting from the different visual weights that make up the visual image and its position on this. When the visual CG and the geometric center coincide, it is recognized that the image is balanced. The action that acts on the balance of the lightness of an image is labeled as the visual weight. The visual weight of a figure is defined from the amount of visible light coming from it and the space occupied by this in the visual image. The colors show us the amount of light coming from a figure, while the shape provides us with information about the space that it occupies. The study explores how the qualities of appearance of three‐dimensional objects affect visual weight and how it can vary due to changes in light, motion of objects or the perspective of the image. Since these calculations can be very complex, we have developed the software called “PesoVisual” that automatically performs these operations on digital color images. Similarly, this software enables the analysis of the variability of the visual image. © 2015 Wiley Periodicals, Inc. Col Res Appl, 41, 175–187, 2016     

Color heterogeneity in visual search

Distractor color heterogeneity refers to a condition in which a target is presented among distractors of different chromaticities. In the present study, the amount distractor color heterogeneity was varied systematically to determine how efficiently the visual system processes displays composed of search elements of multiple colors. Distractor color heterogeneity was expressed by selecting distractor chromaticities from sectors of various angles in a cone‐based normalized color space. The generalizability of the measurements was tested using two different visual search paradigms. An accuracy search task was used in which the search displays were presented as brief flashes and the dependent variable was search accuracy. A latency search task was used in which the display presentation time was under the participant's control and the dependent variable was reaction time. Compared to a homogeneous condition with distractors of a single color, distractor color heterogeneity had a deleterious effect on search performance in both paradigms. In normalized units, the measurements were similar across participants, target chromaticities, and tasks, but the same measurements expressed in non‐normalized units showed clear and systematic individual differences. © 2010 Wiley Periodicals, Inc. Col Res Appl, 2011     

Color appearance of a large homogenous visual field

In this article, the color appearance of a large (85°) homogeneous self‐luminous visual stimulus was studied in a psychophysical experiment. Large stimuli were displayed on a plasma display panal (PDP) monitor. The large stimuli were viewed with a fixed viewing time (2 s). They were compared with 2° and 10° stimuli presented on a grey background on a CRT monitor. The so‐called “color size effect” was found to be significant. The color stimulus was perceived to be lighter when it was large compared with the 2° and 10° situation. But we did not find the general increase of chroma claimed in previous literature. We found only small hue changes. A model of the color appearance of large‐field stimuli is presented in terms of the CIELAB L*, a*, and b* values of the corresponding 2° and 10° stimuli. © 2007 Wiley Periodicals, Inc. Col Res Appl, 33, 45–54, 2008     

Color reproduction of authenticable luminescent backlit transmissive color images

We propose a method for creating authenticable color images under UV excitation backlight by printing an invisible luminescent white emissive ink layer on the verso side of a transmissive substrate and a classical cmy image on the recto side of the substrate. In order to obtain a backlit image whose colors are as close as possible to the original image colors, we map the input image sRGB color gamut into the gamut formed by the emissive white source attenuated by the classical ink halftones. The relationship between surface coverages of the classical cmy ink halftones and the resulting backlit colors is obtained by accounting for the transmission of the emissive white through the paper substrate and through the classical cmy ink halftones. The transmittance of the classical ink halftones is modeled by a new halftone absorbance prediction model. The lightness range of the luminescent backlit color gamut is expanded by printing a black and white UV‐absorbing instance of the original color image in superposition with the luminescent white emissive layer and in registration with the cmy image printed on the recto side. Luminescent backlit color images provide a high anticounterfeiting security, as they combine a verso printed invisible luminescent ink layer, a verso printed black and white instance of the original image and a matching recto printed cmy instance of the original image. The resulting luminescent backlit image colors are close to the original image colors only when observed in transmission mode under UV light. © 2013 Wiley Periodicals, Inc. Col Res Appl, 39, 331–340, 2014     

Heuristic analysis influence of saliency in the color diversity of natural images

The estimation of chromatic diversity of natural images is commonly quantified through the computation of the number of discernible colors and has received much attention because of the different implications it has. However, the relationship between that number and the number of colors that really attracts the attention from an observer is still not clear and has been given little attention. New concepts about salient discernible colors‐the salient chromatic diversity of images‐ and remarkable salient colors‐connected colors in the same salient image area‐are introduced as opposed to the classical number of discernible object colors, which is usually evaluated for the global image without differentiating between probable attended and non‐attended image regions. We have used different well‐known saliency models to locate the salient regions in the scenes and have heuristically studied the extent to which those models preserve the chromatic diversity of natural images. Based on a bottom‐up approach, a reduction of around 40%‐55% in the number of discernible colors were obtained, and not all saliency algorithms preserved a uniform sampling of the original color gamut. Thus, our results suggests that particularly the graph‐based visual saliency model got good low dissimilarity values in comparison with other approaches that put emphasis solely on color as the main low‐level feature. Furthermore, we have introduced a quantification scheme of the average number of remarkable salient colors appearing in the images, and have proved how the heuristic‐based analysis of salient image areas can be used to create segmented images automatically according to their salient chromatic diversity.     

Colour,contrast and gestalt theories of perception: The impact in contemporary visual communications design

Visual communications design, which generally relates to design projects with specific communication objectives, includes most forms of graphic and digital design that have a commercial or an educational purpose. The effectiveness of such design projects rests on how well the embedded communications objectives are met from the perspective of the target audience. In advertising as in education, various post‐campaign evaluation techniques are used to measure effectiveness. The challenge for designers is to create designs that are aesthetically appropriate and visually engaging for the target audience, but which are also functionally‐legible and support the encoding of communication messages so that these are effectively decoded as intended. This is particularly important given that the effectiveness of visual communications is not guaranteed in the visually‐cluttered environment of the 21st century. Of the design elements available to the designer of visual communications, colour and contrast play key roles in visual perception, and the strategic use of these can contribute to the effectiveness of visual communications design. Examining the roles that colour and contrast within the context of Gestalt theories of perception provides additional insight into the ways in which these design elements can be harnessed to improve the effectiveness of visual communications design. © 2013 Wiley Periodicals, Inc. Col Res Appl, 40, 85–92, 2015     

Experimental determination of the laws of color harmony. Part 4: Color preference and the color harmony content

In 1956, we decided at the Budapest University of Technology and Economics to start a large‐scale experiment on color harmony. The experiments and the processing of the experimental results have been completed in 2006. These experiments, described in this article, form a study of how much are people, participating in the experiment, influenced by their own personal color preference in judging the harmony content of a composition. These experiments have utilized the results of former (1958–1969) color preference experiments and the system of color preference indexes, which were developed by the generalization of those results. Within the framework of these experiments, conducted between 1998 and 2006 there were 24 compositions, shown to the participants, at first one by one, then in pairs and at last in groups of six. They had to assess the harmony content of the compositions and award a score on a scale between 0 and 10. Each composition possessed a specific amount of harmony content according to the rules of color space, based on the Coloroid harmony threshold and verified by former experiments. In these experiments the number of elementary observations were 135 568. The people participating in the experiment were approximately equal number of men and women, from the age group between 10 and 70 years. During processing, by using the color preference numerical indexing system, we compared the results of those experiments with the color preference of a similar age group, by using color compositions, identical to the ones used in the present experiment. We have found that the sensation of the color harmony and its intensity have a strong relation to how the observers relate to colors and also their color preferences. The sensation of color harmony is also influenced by the gender and the age of the observer. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 210–224, 2009     

Work week productivity,visual complexity,and individual environmental sensitivity in three offices of different color interiors

This report is the fourth in a series from a large scale study that examines the effects of three office color interiors (white, predominately red, and predominately blue‐green) on worker productivity. Matched on relevant variables, participants were assigned to one of three offices and performed simulated office tasks for four consecutive days. Productivity was measured through workers' task performance and task accuracy, taking into account individual differences in environmental sensitivity (i.e., stimulus screening). The findings suggested that the influences of interior colors on worker productivity were dependent upon individuals' stimulus screening ability and time of exposure to interior colors. Implications of office workers' long‐term productivity are discussed in relation to issues concerning the visual complexity of interior environments. © 2007 Wiley Periodicals, Inc. Col Res Appl, 32, 130 – 143, 2007     

The relationship between visual acuity and color contrast in the OSA uniform color space

OSA uniform color space was used to study the relationship between visual acuity and OSA color contrast. Visual acuity is characterized by 50% minimal separable visual angle using Landolt-C. The OSA color contrast is characterized by the distance between colors in OSA color space. Twenty subjects with normal color vision were tested on 342 test sheets printed with colored Landolt-Cs and background. These results demonstrated that MSVA is approximately inverse log-linearly related to OSA color contrast (R² = 80.4%). Although luminance contrast (R² = 54.2%) is more salient than chromatic contrast (R² = 16.4%), both contrasts can induce very high visual acuity provided that they are sufficiently high. There is also evidence of an additive interaction between chromatic contrast and luminance contrast. Based on these findings, the OSA uniform color space and its color difference formula can be used as a scale for quantifying color contrast to accurately predict the size of colored text or symbols. © 1996 John Wiley & Sons, Inc.     

Color memory matching: Time effect and other factors

The methods of simultaneous and successive, or memory, color matching have been compared for 10 color reference samples distributed in two groups each performed by 50 observers (25 men and 25 women). Our results, obtained with a total of two hundred Munsell color chips arrayed on ten gray cardboard panels, indicate that: (a) while by simultaneous matching the mean color differences obtained are, in most cases, lower than 1 CIELAB unit, those obtained by memory are generally higher; (b) the worst remembered colors are yellow, light green, blue, and pink, and the best remembered color is orange; (c) the influence of the delay time (15 s, 15 min, and 24 h) is significant for the remembered mean color (p < 0.03); (d) we find significant men-women differences for the remembered mean color (p < 0.05). © 1998 John Wiley & Sons, Inc. Col Res Appl, 23, 234–247, 1998     

Color and semiotics: A two-way street

The aim of this article is twofold: to make semioticians interested in visual semiotics better acquainted with the very elaborate aspects of color theory, from which they could take models to develop other aspects of visual semiotics, and to make color theorists more familiar with general semiotics, a paradigm that can encompass and organize the whole study of color. General semiotic notions are described and illustrated with examples taken from the domain of color, and an account of some of the advances of color theory is given within the framework of semiotic categories. Aspects such as color semantics, color grammar, color harmony, color combinations, and others, are reviewed. © 1998 John Wiley & Sons, Inc. Col Res Appl, 23: 390–401, 1998     

Color segmentation in multicolor images using node‐growing self‐organizing map

This article presents a clustering algorithm based on node‐growing self‐organizing map (NGSOM) to classify colors on color images automatically and accurately partition the regions of different colors for color measurement. Based on the CIEDE2000 criterion, pixels in a multicolor image are grouped into a number of visually distinguishable color regions in which pixel distribution information is provided as the input of the NGSOM network for further segmentation. As an unsupervised clustering algorithm, the NGSOM randomly selects two initial nodes from the input source without a predefined network structure and grows nodes according to color differences between the first best matching unit (FBMU) and the second best matching unit (SBMU) of the current input data. Unlike a traditional SOM, the NGSOM utilizes learning rates varying with the pixel distributions of major color regions. The node‐growing procedure is terminated when all the input data are examined. Compared with some commonly used color clustering algorithms, the proposed algorithm possesses a better peak signal‐to‐noise ratio (PSNR) and higher time efficiency. The NGSOM can be used for a wide range of applications, including fabric colorfastness assessment, painting conservation, and scenic identification in aerial images.     

Color and culture: Innovations and insights since Basic Color Terms—Their Universality and Evolution (1969)

Fifty years ago, in 1969, Berlin & Kay published Basic Color Terms—Their Universality and Evolution and set in‐motion a large‐scale systematic research program for studying color naming and categorization across first‐language speakers from different ethno‐linguistic societies. While it is difficult to gauge the impact a research program can make over 50‐years, many linguists, anthropologists, cognitive scientists, and perceptual psychologists consider the Berlin & Kay book as one of the top‐most influential works in cross‐cultural studies not only of color linguistics, but of cognition and language more generally. Today reverberations from the Berlin & Kay (1969) research program continue to resonate through recently available data sets that are being examined with new quantitative analysis methods and modeling approaches. Here we review the origins of the Basic Color Terms phenomenon, and note a few of the numerous directions from which on‐going related work continues to bring forth interesting results in the color categorization arena.     

Associations of visual forms with colors: The minor role of emotion as the mediator

Associations of colors with a wide variety of visual forms were examined. Fifty visual forms were presented to Japanese participants, who were asked to report a color suitable to each visual form out of 15 colors. Correspondence analysis was applied to the responses, and four dimensions of configurations were obtained. The first and second dimensions were related to chromaticity or hue. In these dimensions, red and orange were associated with round symmetric shapes, yellow with shapes with sharp corners, violet and purple with irregular shapes with smooth curves, and cold colors such as blue and green with forms that consisted of simple geometrical elements such as triangles, squares, and circles. The third dimension was related to L* and b* in the CIELAB color space and to the stability of visual forms. Dimension 4 was not significantly related to any of L*, a*, and b*. In another experiment, participants rated the affective impressions of the colors and visual forms on semantic differential (SD) scales. The analyses of the SD data combined with the results of the color‐form associations suggest that the role of emotional meanings of colors and visual forms in mediating the associations was rather minor, and that world‐knowledge contributed considerably to the observed color‐form associations. Kandinsky's color‐form assignment was also examined, and except for the yellow‐triangle association, the assignment was not supported.     

Comparison of visual and automated colorimeter for refined and bleached cottonseed oils

Color as a fundamental quality of edible oils has been determined primarily by visual comparison. The automatic colorimeters introduced recently made it possible to avoid operator variability associated with visual color measurement. The feasibility of using an automatic colorimeter, Colourscan, to measure the color of refined and bleached cottonseed oils was investigated. Good agreement, r²=0.99, between automatic color readings vs. visual color measurement by using the Lovibond-AOCS Color Scale was obtained. Near-linear correlation of light paths from 133.4 to 2.5 mm permits dark oil to be assessed with the automatic colorimeter.     

Proposal for selecting two‐color combinations with various affections. Part II: Demonstration of the system

The characteristics of the proposed color selection system are shown using several colored figures of two‐color combinations selected by the system. There are four kinds of color feelings in the system, and each feeling is classified into three categories (i.e., high, intermediate, or low). The feelings used are pleasantness, contrast, floridness, and warmth. Users can try the 3⁴ = 81 combinations of feelings by setting the categories for four kinds of feelings. The differences among categories of color feelings are also shown by several colored figures. It is difficult to describe the differences by words. However, it is rather easy to describe by pictures. The proposed color selection system is expected to be a useful tool for assisting color designers. Comments about the proposed system from potential users are reported. © 2009 Wiley Periodicals, Inc. Col Res Appl, 34, 135–140, 2009     

Orphics: Computer Graphics and the Feasibility of a Preferred Color Order

Because color has lost its permanent form in certain media such as computer displays, there is a need for some overriding organizational principle. In earlier work on orphics, this author has discussed some ideas and techniques for the fluid articulation of color in space and time without relying on a preferred color order. In this article the possibility of defining a sequence of colors arranged in a unique order, that is, general enough to serve as a tuning for the composition of color in space and time, is discussed. to gain as wide a perspective as possible, color vision theories and their relevance are discussed, as well as the structural compatibilities between color orders and the well-tempered musical scale. Finally the works of two artists, Morgan Russell and Robert Delaunay, are examined.     

Color corrected single scale retinex based haze removal and color correction for underwater images

Underwater images are affected by scattering of dust particles leading to hazy images. The difference in absorption of light at different wavelength leads to colorcast. Restoring underwater images from haze and colorcast degradation is a challenging task. This article proposes color corrected single scale retinex algorithm for the restoration of hazy and colorcast underwater images. Further, the illumination of the underwater image is enhanced through illumination enhancer. In order to correct colorcast, the underwater images intensity shifters are proposed. Blur, natural image quality evaluator, blind/referenceless image spatial quality evaluator, entropy, peak signal to noise ratio are the metrics used to evaluate the performance of the proposed restoration technique and compared the output with the existing techniques. Compared to the existing techniques the proposed algorithm prominently removes haze and colorcast present in underwater images. The study excludes retinex-with-reset models from consideration.