Hue Variation Research Articles

Visual perception of surface wetness

We can visually recognize a variety of surface state. Just a quick look is sufficient to find the bath floor is dry, the road in front is slippery, the window glass is frosty, or the ornament is dusty. If a given surface state perception relies on the analysis of diagnostic image features, an effective strategy to reveal those features and the associated visual processing is to find a stimulus transformation that alters the apparent surface state. Here we report an image transformation that makes dry objects look wet. This wet filter consists of two operations: (1) Tone-remapping with an accelerating nonlinear function that renders the intensity histogram positively skewed: (2) color saturation enhancement. In an experimental test, we applied the wet filter to a variety of natural textures of the McGill Calibrated Colour Image Database. The results of a wetness rating experiment showed that the wet-filtered images were perceived as wetter than the original images. In addition, the perceived wetness depended on the variance of hue. The wet-filter was less effective for images with a small variance of hue. Optically, wetting a surface tends to increases the specular reflection. In addition, as the incoming light scatters repeatedly within the surface liquid layer, the light going out from the surface tends to be darker and more saturated. The effects of these optical changes can be simulated by the two wet-filter operations. However, positively skewed luminance histogram and high chromatic saturation may be caused by other factors - for instance, the visual scene may happen to include highly saturated glossy objects. This is presumably why hue variation matters. If the same image transformation simultaneously occurs in many different objects, the brain infers that the change likely has the same cause, such as water shower in the present case. Meeting abstract presented at VSS 2015. Language: en

A robust segmentation method for counting bovine milk somatic cells in microscope slide images

Mastitis is an infectious disease associated with the increased number of somatic cells in cow’s milk, and it is one of the most relevant cause of economic losses in dairy farming industries. In this paper, we propose a method capable of determine, with 99.7% accuracy, the number of these cells in microscope slide images. This level of accuracy is achieved by changing the image original RGB format to Lab color space and applying k-means clustering algorithm to remove debris and other background features. A new gray level thresholding is proposed, and the remaining bound cells are separated in the final segmentation step applying Watershed transform. Many microscope slide images with debris, contrast, and hue variation were used to validate the experimental results. Comparison between the proposed method and manual counting indicates that this new approach is a robust and promising solution to be incorporated in a future automated somatic cell counting system using optical microscopy.

Exploring the molecular basis of monarch butterfly color pattern variation: a response to A. Hume's 'Myosin--a monarch of pigment transport?'.

Exploring the molecular basis of monarch butterfly color pattern variation: a response to A. Hume's 'Myosin--a monarch of pigment transport?'.

Genetic basis and fitness correlates of dynamic carotenoid-based ornamental coloration in male and female common kestrels Falco tinnunculus.

Knowledge of the genetic basis of sexual ornaments is essential to understand their evolution through sexual selection. Although carotenoid-based ornaments have been instrumental in the study of sexual selection, given the inability of animals to synthesize carotenoids de novo, they are generally assumed to be influenced solely by environmental variation. However, very few studies have directly estimated the role of genes and the environment in shaping variation in carotenoid-based traits. Using long-term individual-based data, we here explore the evolutionary potential of a dynamic, carotenoid-based ornament (namely skin coloration), in male and female common kestrels. We first estimate the amount of genetic variation underlying variation in hue, chroma and brightness. After correcting for sex differences, the chroma of the orange-yellow eye ring coloration was significantly heritable (h2±SE=0.40±0.17), whereas neither hue (h2=0) nor brightness (h2=0.02) was heritable. Second, we estimate the strength and shape of selection acting upon chromatic (hue and chroma) and achromatic (brightness) variation and show positive and negative directional selection on female but not male chroma and hue, respectively, whereas brightness was unrelated to fitness in both sexes. This suggests that different components of carotenoid-based signals traits may show different evolutionary dynamics. Overall, we show that carotenoid-based coloration is a complex and multifaceted trait. If we are to gain a better understanding of the processes responsible for the generation and maintenance of variation in carotenoid-based coloration, these complexities need to be taken into account.

History and mechanisms of carotenoid plumage evolution in the New World orioles ( Icterus )

While many recent studies focus on the functions of carotenoids in visual signaling, they seldom address the phylogenetic origins of plumage coloration and its mechanisms. Here, we used the New World orioles (Icterus) as a model clade to study the history of orange carotenoid-based coloration and pigmentation, sampling 47 museum specimens from 12 species. We examined the identity and concentration of carotenoids in oriole feathers using high-performance liquid chromatography, and used phylogenetic comparative methods to compare these observations to reflectance measurements of plumage. Each of the seven yellow oriole species we sampled used only lutein to color their feathers. Ancestral state reconstruction of this trait suggests that the oriole common ancestor had yellow feathers pigmented with lutein. We found keto-carotenoids in small concentrations in the plumage of each of the five species scored as orange. This correlation suggests that discrete gains and losses of keto-carotenoids are behind independent gains of orange coloration in orioles. In contrast, total carotenoid concentration was not associated with hue, and total concentration of keto-carotenoids poorly explained variation in hue among species where they were present. These findings suggest that orioles most likely evolved orange plumage coloration at least twice, each time by gaining the ability to metabolize dietary carotenoids by C4-oxygenation. Given that red coloration is generated by this same oxygenation process in a wide range of bird species, it raises the question of why, if orioles possess this metabolic capability, no red oriole species exist.

Maternal effects and warning signal honesty in eggs and offspring of an aposematic ladybird beetle

Summary The eggs of oviparous species are often subject to intense predation pressure. One parental strategy to deter predators is to produce eggs that are laced with noxious chemicals and are conspicuously coloured (i.e. aposematism). Ladybird eggs are conspicuously coloured and contain alkaloids; these traits are believed to function in concert as visual signal and chemical defence, respectively, to deter predators. However, it remains unclear whether such aposematic signals reveal the strength (rather than simply the existence) of chemical defences. Furthermore, additional functions of egg pigments and toxins could apply; in particular, mothers might deposit such resources into eggs to aid the development of offspring or to provide resources that could contribute to aposematic traits in offspring. We bred wild‐caught seven‐spot ladybird beetles (Coccinella septempunctata) in the laboratory and then measured relationships between egg coloration and toxin concentrations (i.e. the alkaloids precoccinelline and coccinelline). We also measured relationships between egg carotenoids and egg coloration, and between egg coloration and toxin levels, and the elytra coloration and toxin concentrations of offspring at eclosion for a subset of eggs that were allowed to develop. Egg carotenoids predicted egg colour saturation. In turn, egg colour saturation and hue positively predicted egg concentrations of precoccinelline. However, there were no significant relationships between egg coccinelline concentration and any measure of egg coloration. In recently eclosed adults of both sexes, elytra saturation was significantly explained by variation in egg saturation and hue. Finally, body concentrations of coccinelline were significantly explained by variation in elytra hue. These results suggest that the coloration of C. septempunctata eggs is a reliable signal of the strength of chemical defences contained therein, but in addition, maternal investment of pigments and toxins into eggs may serve to influence the reliability of aposematic signalling in resultant offspring.

Colour influences sensory perception and liking of orange juice

This study assesses the effect of slight hue variations in orange juice (reddish to greenish) on perceived flavour intensity, sweetness, and sourness, and on expected and actual liking. A commercial orange juice (COJ) was selected as a control, and colour-modified orange juices were prepared by adding red or green food dyes (ROJ and GOJ) that did not alter the flavour of the juice. A series of paired comparison tests were performed by 30 naive panellists to determine the influence of orange juice colour on flavour intensity, sweetness, and sourness. Then, 100 orange juice consumers were asked to rate expected liking of orange juice samples initially by visual evaluation and subsequently for actual liking upon consumption, using a labelled affective magnitude scale. Results of pair comparison tests indicated that colour changes did not affect flavour intensity and sweetness, but the greenish hue (GOJ) significantly increased the perceived sourness. Results of the consumers’ study indicated significant differences in expected liking between the orange juice samples, with ROJ having the highest expected liking. However, scores of actual liking after consumption were not significantly different. COJ and GOJ showed a significant increase in actual liking compared to expected liking. This study shed light on how slight variations in orange juice hue (reddish to greenish hues) affect the perceived flavour intensity, sweetness, and sourness, and the expected and actual liking of orange juice.

<p>Effect of pre-defined Color Rendering Intents (CRI) on the Hue attributes in a Color Managed Workflow (CMW)</p>

The purpose of this study is to determine the influence of applied International Color Consortium (ICC) predefined color rendering intents on the digital printing solid colors output (Cyan, Magenta, Yellow, and Black ((CMYK]) hue and gray output (Overlap of CMY: 50%, 40%, and 40% tints) hue variation among the four ICC standard color rendering intents in a color management workflow (CMW). The experiment analyzed the effect of four ICC-specified color rendering intents (absolute, perceptual, relative, and saturation intents) on the digital color output hue of gray and solid colors. The objective of this study allowed testing of an accepted color management practice to gain a better understanding of the presumptions associated with the application of rendering intents. The experiment examined the four ICC color rendering intents as independent groups (K = 4) using a one-way analysis of variance (ANOVA) with equal n’s method (at α = 0.05) to determine the significant colorimetric variation (COLVA) of hue between the (K = 4, n = 15, and N =60) group means (averages) color deviations of these intents. With four rendering intents (groups, K = 4), a one-tailed, non-directional hypothesis was established. The conclusions of this stilly arc based upon an analysis of ANOVA test data and associated findings. The data from the ANOVA reveal significant differences in the gray hue deviation of the reproduction among the multiple ICC color rendering intents (CRT). The colorimetric data suggest that selection of a rendering intent is an important activity in a CMW as it relates to obtaining accurate output colors for a desired purpose.

Decoupling the dual source of colour alteration of architectural titanium: Soiling or oxidation?

The advanced structural properties of titanium, together with its fascinating interference colours, have opened the way to architectural applications as façade claddings. Yet, several problems of soiling and gradual corrosion tend to alter its aesthetic properties. Atmospheric exposure tests on titanium and anodised titanium were performed, and surface colour was monitored with spectrophotometry to evaluate both corrosion and soiling extent. In all cases, a slight surface oxidation was observed, which decreased with increasing initial thickness of the anodic film. The use of lightness as main parameter to quantify soiling must be carefully considered, as lightness variations must also take into account the influence of oxide hue variation.

Novel software for quantitative evaluation and graphical representation of masticatory efficiency

Blending of chewing gums of different colours is used in the clinical setting, as a simple and reliable means for the assessment of chewing efficiency. However, the available software is difficult to use in an everyday clinical setting, and there is no possibility of automated classification of the patient's chewing ability in a graph, to facilitate visualisation of the results and to evaluate potential chewing difficulties. The aims of this study were to test the validity of ViewGum - a novel image analysis software for the evaluation of boli derived from a two-colour mixing ability test - and to establish a baseline graph for the representation of the masticatory efficiency in a healthy population. Image analysis demonstrated significant hue variation decrease as the number of chewing cycles increased, indicating a higher degree of colour mixture. Standard deviation of hue (SDHue) was significantly different between all chewing cycles. Regression of the log-transformed values of the medians of SDHue on the number of chewing cycles showed a high statistically significant correlation (r² = 0.94, P < 0.01). ViewGum eliminates drawbacks of previous two-colour chewing gum test methods by the simplicity of its application. The newly developed ViewGum software provides speed, ease of use and immediate extraction of clinically useful conclusions to the already established method of chewing efficiency evaluation and is a valid adjunct for the evaluation of masticatory efficiency with two-colour chewing gum.

When does fading enhance perceptual category learning?

Training that uses exaggerated versions of a stimulus discrimination (fading) has sometimes been found to enhance category learning, mostly in studies involving animals and impaired populations. However, little is known about whether and when fading facilitates learning for typical individuals. This issue was explored in 7 experiments. In Experiments 1 and 2, observers discriminated stimuli based on a single sensory continuum (time duration and line length, respectively). Adaptive fading dramatically improved performance in training (unsurprisingly) but did not enhance learning as assessed in a final test. The same was true for nonadaptive linear fading (Experiment 3). However, when variation in length (predicting category membership) was embedded among other (category-irrelevant) variation, fading dramatically enhanced not only performance in training but also learning as assessed in a final test (Experiments 4 and 5). Fading also helped learners to acquire a color saturation discrimination amid category-irrelevant variation in hue and brightness, although this learning proved transitory after feedback was withdrawn (Experiment 7). Theoretical implications are discussed, and we argue that fading should have practical utility in naturalistic category learning tasks, which involve extremely high dimensional stimuli and many irrelevant dimensions.

Eco-Dyeing of Wool Using Aqueous Extract of the Roots of Indian Madder (Rubia cordifolia) as Natural Dye

The aqueous extract obtained from the powdered roots of Indian madder (Rubia cordifolia) was used for dyeing of woolen yarns. The effect of pH, dye concentration, and mordants on the colorimetric and fastness properties has been studied. Brilliant shades of bright red to scarlet were obtained with significant variation in hue and tone of shades depending on mordants and dye concentrations used. The color coordinates of the dyed samples were found to be in the red-yellow quadrant of the CIELab color space. It was found in all cases that mordanting with alum as well as ferrous sulfate has caused decrease in lightness (L*) values and increase in K/S values. All the dyed samples exhibited commercially acceptable fastness to light, washing, and rubbing. Scanning Electron Microscopy (SEM) morphological studies have also been performed on different woolen yarns.

Stereoscopic depth perception varies with hues

The contribution of color information to stereopsis is controversial, and whether the stereoscopic depth perception varies with chromaticity is ambiguous. This study examined the changes in depth perception caused by hue variations. Based on the fact that a greater disparity range indicates more efficient stereoscopic perception, the effect of hue variations on depth perception was evaluated through the disparity range with random-dot stereogram stimuli. The disparity range was obtained by constant-stimulus method for eight chromaticity points sampled from the CIE 1931 chromaticity diagram. Eight sample points include four main color hues: red, yellow, green, and blue at two levels of chroma. The results show that the disparity range for the yellow hue is greater than the red hue, the latter being greater than the blue hue and the disparity range for green hue is smallest. We conclude that the perceived depth is not the same for different hues for a given size of disparity. We suggest that the stereoscopic depth perception can vary with chromaticity.

Color-appearance-model based fusion of gray and pseudo-color images for medical applications

Fusion of gray and pseudo-color images presents more information of biological tissues in a single image and facilitates the interpretation of multimodalities in medical practice. However, fused results are hampered by the problems of blurred details, faded color and artifact contours. This paper reports a method to solve the problems by precisely predicting the attributes of color perception using the color appearance model of International Commission on Illumination published in 2002 (CIECAM02). First, a rainbow palette is generated from the color attributes. It is uniform in lightness, and thus the valuable information of pseudo-color image can be totally sealed in its chromatic properties. Then the fusion process is carried out with the adjustment of gray image in lightness. Here, the predicted hue and saturation of pseudo-color image is merged with the predicted lightness of gray one. Therefore, information of two original images exists separately in achromatic and chromatic properties of the resulting image. Based on different color spaces (CSs) and color appearance models (CAMs), the color aggregations available for displaying fused images are presented and compared. The aggregation based on the CIECAM02 exhibited more uniform variation in lightness and hue. Fused results of simulated lesion and breast phantom manifested the compromise between the scope of gray and the perception of color. Furthermore, in the quantitative experiment on 49 sets of simulated ultrasound and strain images, the visual information fidelity (VIF) was applied to assess the similarity between the result and its sources. It revealed the superiority of the proposed method over the traditional ones including CSs-based methods, transparency technique, alternating display technique, frequency encoding methods, and maximum-selection-rule based rules. The results of two clinical cases demonstrated its practicality in medical applications. Besides, its feasibility in fusing two high-resolution structural images was preliminarily approved based on the simulated MRI data.

The transcription factor LhMYB12 determines anthocyanin pigmentation in the tepals of Asiatic hybrid lilies (Lilium spp.) and regulates pigment quantity

A single dominant locus determines anthocyanin biosynthesis in the tepals of Asiatic hybrid lilies (Lilium spp.); however the gene that determines this trait has not been previously reported. Furthermore, anthocyanin colour hue in tepals varies between cultivars, but the mechanisms underlying this variation are not known. Here, we show that LhMYB12, which is homologous to petunia An2, determines anthocyanin pigmentation in tepals and that the level of LhMYB12 transcription affects the quantity of anthocyanin pigments, producing colour hue variation in tepals. The pink-tepal cultivars Montreux and Renoir were heterozygous for the LhMYB12 gene. Their F1 population segregated 3:1 for the presence or absence of anthocyanin in tepals, and LhMYB12 cosegregated perfectly with the presence of anthocyanin, indicating that LhMYB12 determines anthocyanin biosynthesis in tepals. Among seven cultivars, a single anthocyanin cyanidin 3-O-β-rutinoside was detected in tepals displaying light pink, pink–red, dark red, or chocolate brown hues. However, concentrations differed according to the following order of colour hue: light pink < pink–red < dark red < chocolate brown, suggesting that colour hue variation in tepals is strongly related to anthocyanin quantities. The accumulation of LhMYB12 transcripts in tepals varied between seven cultivars in the same order, and transcription levels were positively correlated with pigment quantities. This suggests that the levels of transcription of LhMYB12 vary among the different cultivars and subsequently affect the quantities of pigment in tepals. These results indicate that LhMYB12 determines anthocyanin pigmentation and generates the variation in anthocyanin colour hue in lily tepals.

Monitoring Effects of Ethanol Spray on Cabernet franc and Merlot Grapes and Wine Volatiles Using Electronic Nose Systems

The ability of two electronic nose systems (conducting polymer and surface acoustic wave-based) to differentiate volatiles of grapes and wines treated with an aqueous ethanol spray (5% v/v) at veraison was evaluated. Ethanol spray induced fruit ethylene production immediately posttreatment, which then declined progressively. The electronic nose evaluations of grape volatiles were compared with Cabernet franc and Merlot physicochemistry and with wine gas chromatographic and aroma sensory data. Canonical discriminant and principal component analysis found that both electronic nose systems and the physicochemical measures (Brix, TA, pH, color intensity and hue, total phenols, glycosides, and berry weight) were able to discriminate between ethanol-treated and untreated grapes and wines for both cultivars. Grape physicochemical treatment differences were due mainly to variations in hue, phenolic-free glycosides, and total phenols. Aroma sensory evaluations using a consumer panel differentiated between ethanol treatments and controls for Merlot, but not for Cabernet franc wines.

Skin colorimetric parameters involved in skin age perception

Age perception is based on a number of facial attributes such as wrinkles, skin gravity effects, feature lines, and skin optical appearance. The colorimetric and optical diffusion properties of skin have been compared with the consumer interpretation of 'skin age' of cheek area pictures without wrinkles or feature lines. Controlled lighting images of skin were taken with the Visia CR. Skin sections from the cheek area were selected without eye region wrinkles or naso-labial lines for consumer interpretation. These same skin sections were analyzed for optical roughness and colorimetric parameters in the LCH color space, by distinguishing several roughness parameters according to their physical scale. Three main optical parameters of skin were found to influence the consumer's interpretation of skin 'visual age': the chroma (color saturation), lightness, and the local light-diffusing ability of skin. For the chroma and lightness, mainly large-scale inhomogeneities in the 0.8-2 cm(-1) range are taken into account by the consumer. Surprisingly, variations in the skin hue show a total absence of correlation with the consumer grading.

Apparent motion depending on luminance and hue variations

Apparent motion depending on luminance and hue variations

In situ microscopy observation of liquid flow, zirconia growth, and CO bubble formation during high temperature oxidation of zirconium diboride–silicon carbide

The oxidation of ZrB 2–SiC composites at 1450–1650 °C was directly observed with in situ optical microscopy. Video frames showed the flow of silicate liquids, the formation of zirconia deposits, and the growth and collapse of gaseous bubbles on the oxide surface. Contrast in the incandescence of in situ images is analyzed as spatial variations in hue and intensity and related to differences in emissivity of the oxide scale surface features by comparing these hot images with room temperature images. Above 1450 °C, gaseous bubbles were observed to grow and collapse causing perturbations in the liquid oxide on the surface. The bubbles are associated with the evolution of CO from SiC oxidation and the onset is related to the critical temperature where the partial pressure of CO under the oxide scale exceeds atmospheric pressure.

Functionalization of ceramic tile surface by soluble salts addition: Part I

The aim of this investigation was the surface functionalization of industrial ceramic tiles by soluble salts addition to improve mechanical properties (resistance to scratch and wear) preserving the aesthetical aspect of the final product. This objective was pursued through the application of different solution of zirconium capable to be transformed in zirconia nanoparticles during the material sintering. The solutions, in different concentrations, were deposited (300 g/m 2) on unglazed green tiles by air-brushing. The obtained products were polished and characterized in terms of microstructure, surface micromechanical and technological properties based on the UNI EN ISO reference rules. The final aesthetical aspect of the products and the obtained hue variation were evaluated by means of UV–vis spectroscopy and colorimetric analysis.