Small Color Research Articles

About quantifying small color differences in digital images

We discuss aspects of the use and possibilities provided by three-color colorimeters or digital cameras in problems of detecting small color differences by computer vision methods. The spectral dependence of the total color differences between pairs of visually indiscernible monochromatic stimuli is experimentally revealed. An experimental setup based on the UM-2 monochromator is created for producing a digital atlas of monochromatic stimuli at 1-nm increments. The atlas serves to test the color gamut and color differentiation of cameras. It is experimentally shown that in the visible spectral range a color difference of 3 units is detected by pairs of stimuli that are unevenly distributed across the spectrum and differ in wavelengths from 1 to 6 nm. The capabilities of computer vision are tested on the examples of identifying additional texts during a technical and forensic examination of documents. A new algorithm is developed for finding and quantitatively characterizing color difference of inserts based on a digital image of the inscription. In the algorithm, the objective analysis of the image is divided into a block of color segmentation and that of color tone and color difference assessment. With such an approach, the color segmentation block performs preprocessing functions, making a border map for the classes with different colors for the subsequent calculations. The Otsu method of optimal global threshold transformation is for the first time applied to a problem of image segmentation by color saturation. The trial of the algorithm confirms its efficiency in the solution of expert tasks.

52‐4: Late‐News‐Paper: Development of 240Hz Refresh Rate ADS Mode Gaming Product

The ADS display mode shows significant advantages of high transmittance, wide viewing angle, small color shift at large view angle, etc., and thus has been widely used in all kinds of display product such as mobile phone, tablet, notebook, monitor and television. However, ADS mode shows shortcomings of slow response speed. In this work, we made extreme optimization research and breakthroughs in improving ADS mode response speed from the aspects of LC material, cell gap, and pixel ITO slit angle. Based on the research, 27 inch FHD 240Hz refresh rate gaming product was successfully developed. It has been achieved gray to gray average response time 1.9ms with over driving as well as contrast ratio 1214:1 fulfilling static CR requirements of VESA HDR standard.

International observational campaign of the 2014 eclipse of EE Cephei

Context. EE Cep is one of few eclipsing binary systems with a dark, dusty disc around an invisible object similar to ε Aur. The system is characterised by grey and asymmetric eclipses every 5.6 yr that have significant variations in their photometric depth, ranging from ∼0.m5 to ∼2.m0. Aims. The main aim of the observational campaign of the EE Cep eclipse in 2014 was to test the model of disc precession. We expected that this eclipse would be one of the deepest with a depth of ∼2.m0. Methods. We collected multicoloured observations from almost 30 instruments located in Europe and North America. These photometric data cover 243 nights during and around the eclipse. We also analyzed low- and high-resolution spectra from several instruments. Results. The eclipse was shallow with a depth of 0.m71 in the V band. The multicoloured photometry illustrates small colour changes during the eclipse with a total amplitude of order ∼+0.m15 in the B − I colour index. We updated the linear ephemeris for this system by including new times of minima, measured from the three most recent eclipses at epochs E = 9, 10, and 11. We acquired new spectroscopic observations, covering orbital phases around the eclipse, which were not observed in the past and increased the data sample, filling some gaps and giving better insight into the evolution of the Hα and Na I spectral line profiles during the primary eclipse. Conclusions. The eclipse of EE Cep in 2014 was shallower than expected, measuring 0.m71 instead of ∼2.m0. This means that our model of disc precession needs revision.

<p><strong>Description of <em>Kelypitnus steineri</em>, a minute-sized spider beetle (Coleoptera: Ptinidae) from Madagascar</strong></p>

A new endemic Madagascan genus and species of spider beetle from Toliara Province in southwest Madagascar is described. The genus Kelypitnus gen. nov. is characterized by its small size and dark brownish-black color, a short lateral margin on the pronotum, a concave proventrite, 10-segmented antennae, and the presence of a small, conspicuous raised ring with a central cavity on the first abdominal ventrite in the male. The single species, Kelypitnus steineri sp. nov. is diagnosed, described, and illustrated and compared to the two most similar genera known, Neoptinus Gahan and Pitnus Gorham. Key words: Kelypitnus, Coleoptera, Ptinidae, new genus, Madagascar, Bostrichoidea, endemic

Hybrid Tandem White OLED with Long Lifetime and 150 Lm W−1 in Luminous Efficacy Based on TADF Blue Emitter Stabilized with Phosphorescent Red Emitter

AbstractModern lighting requires high efficiency and long lifetime simultaneously. In this paper, highly efficient white organic light emitting diodes (WOLEDs) are demonstrated based on a modified hybrid tandem structure constructed with a phosphorescent yellow‐red unit using an exciplex host and a blue‐red unit based on a thermally activated delayed fluorescence (TADF) blue emitter, and the devices are properly built with internal and external light extraction structures. The resulting four‐color WOLED exhibits an external quantum efficiency and luminous efficacy of 126.2% and 150.7 Lm W−1, respectively, and the color rendering index is close to 80 at a brightness of 1000 cd m−2. This device also shows a very good color stability with increasing luminance up to 15 000 cd m−2 and there is only a small angular color variation for viewing angles changing from 0° to 70°. The T50 lifetime (defined as the time corresponding to 50% decrease in luminance from an initial value) of the WOLED at an initial luminance of 1000 cd m−2 is extrapolated as 12 600 h.

Observer metamerism to display white point using different primary sets.

Displays with different primary sets were found to introduce perceived color mismatch between stimuli that are computationally metameric and to affect the variations of the perceived color difference of metameric stimuli among observers (i.e., observer metamerism). In this study, computational analyses and psychophysical experiments were carried out to investigate the possibilities of increasing the color gamut area of a commercially available liquid crystal display (LCD) system using 16 three-primary sets, so that the perceived color difference of the white point between the system and the reference display and observer metamerism can be minimized. It was found the primary set with the peak wavelengths of 450, 525, and 665 nm was able to increase the sRGB color gamut by 72.1% in the CIE 1931 chromaticity diagram, which was found to have a strong correlation to the color volume of wide color gamut displays, while introducing the minimal color mismatch to the white point of the reference display and observer metamerism. The small white point color mismatch could be due to the similar wavelengths of the blue and green primaries in comparison to the reference display. In addition, the experiment results suggested that the CIE 2006 2° Color Matching Functions (CMFs) had better performance in characterizing the color match of the white point than the CIE 1931 2°, 1964 10°, and 2006 10° CMFs, which could be due to the fact that the stimulus used in the experiment only had a field of view (FOV) around 3.8°.

Application of genetic algorithm to color recipe formulation using reactive and direct dyestuffs mixtures

AbstractColor reproduction is a science in constant development. In this article, a new model to solve the color recipe prediction problem using a genetic algorithm is proposed. The objective is to optimize the color recipe prediction stage by determining the dyes to use in a mixture and their respective proportions to reproduce the target color. Two ranges of dyes were used for dyeing 100% cotton woven fabrics: three reactive dyes (CI Reactive Red 238, CI Reactive Yellow 145, and CI Reactive Blue 235) and four direct dyes (CI Direct Orange 34, CI Direct Red 227, CI Direct Blue 85, and CI Direct Black 22). The criterion of optimization, in reproducing the desired shades, is to minimize the CMC color difference between the desired reference color and the color resulting of the predicted recipe. The proposed algorithm revealed good results with small CMC color differences between target and reproduced colors. The effectiveness of the algorithm was also evaluated and proven by calculating errors between the predicted concentrations in the proposed recipes and the actual concentrations.

Plumage coloration and morphometrics of the Little Owl Athene noctua in the Western Palearctic

The Little Owl is a species with a wide range in the Palearctic. Thirteen subspecies have been described based on small coloration or size differences. Recently, genetic studies in the western portion of the European range have shown the presence of some well distinct clades. We examined the variation in structural size and coloration of Western Palearctic birds, with particular attention to the pattern of light and dark pigmentation on the tail, and we checked for the presence of UV reflection through reflectance spectroscopy. We did not find clear-cut differences in size or plumage between the currently accepted subspecies, nor between individuals pertaining to the different genetic clade areas. There is a trend for individuals from the western genetic clade (Iberia, France, England and central Europe) to have longer tarsus with smaller wings, while individuals from the eastern generic clade (Balkans) have an opposite pattern. Italian birds are intermediate. The tail of Balkan birds has a wider dark pigmentation, with reduced light spots. Little owl feathers do not show reflectance in the UV part of the spectrum. We found a very large variation of morphological and color patterns between individuals collected in the same geographical area. Currently, the arrangement of individuals to any Little owls' subspecies on morphological data appears to be a very difficult task.

Nodularity-like appearance in the cardia: novel endoscopic findings for Helicobacter pylori infection

Background and study aims Helicobacter pylori -associated nodular gastritis, which is associated with follicular lymphoid hyperplasia, is mainly recognized in the antrum. However, we have also observed nodularity-like appearance in the cardia. This study aimed to investigate the clinical significance of cardiac nodularity-like appearance in H. pylori -associated gastritis. Patients and methods Patients who underwent esophagogastroduodenoscopy and were evaluated for H. pylori infection for the first time were enrolled. A nodularity-like appearance in the cardia was defined as a miliary nodular appearance or scattered appearances of small circular whitish coloration. H. pylori infection was diagnosed according to serum anti- H. pylori antibody and the urea breath test or histology. Accuracy of the H. pylori infection diagnoses based on nodularity-like appearance were assessed. Results Among 265 patients, 42 patients (15.8 %) were diagnosed as positive for H. pylori . Cardiac nodularity-like appearance and antral nodularity were recognized in 25 and 15 patients, respectively. In accuracy of predicting H. pylori by cardiac nodularity-like appearance, specificity was 0.996, sensitivity was 0.571, positive predictive value was 0.960, negative predictive value was 0.925, and accuracy was 0.928. The sensitivity of cardiac nodularity-like appearance was significantly higher than that of antral nodularity ( P = 0.0284). Conclusions Cardiac nodularity-like appearance had a high accuracy rate for H. pylori infection diagnosis. Cardiac nodularity-like appearance was found more frequently than antral nodularity.

Experimental investigation on the durability of a novel lightweight prefabricated reinforced-EPS based construction system

This paper investigates the durability of a low-cost construction system named HOMEDONE developed to realize affordable and also temporary housing solutions. The system is based on the assembly of 3D-reinforced EPS panels externally topped off with a multi-layer rendering system. Similar technologies showed durability issues, especially in hot climates, due to the thermal and hygrometric stresses of the thin finishing layers when coupled to thick EPS panels and exposed to extreme events. For this reason, in this work freeze–thaw and wet/drying-UV aging tests on HOMEDONE panels with different finishing systems have been carried out, monitoring macroscopic, microscopic (ATR-FT-IR analysis) and bond strength variations due to aging. Results have pointed out good mechanical properties of the system and only small color variations of the finishing layer due to UV cycles. Then, HOMEDONE can be considered as a durable option for affordable and temporary housing solutions.

Antibacterial Finishing of Vat Dyed Cotton Fabrics with a Reactive N-Halamine

To obtain antibacterial properties for colored cotton fabrics, vat dyes were chosen to dye cotton because they can avoid serious discoloration during chlorination. In this study, we synthesized a reactive N-halamine precursor, 4-(4-(2,2,6,6-tetramethyl-4-piperidinol)-6-chloro-1,3,5-triazinylamino)-benzenesulfonate (BTMPT), and coated it on colored cotton fabrics that were dyed with three different vat dyes. The optimum pH for chlorination of the treated cotton fabrics was investigated. Chlorination at pH 11 achieved a small color difference and greater than 0.2% of active chlorine loading. When challenged, the chlorinated fabrics inactivated all inoculated Staphylococcus aureus (Gram-positive) and Escherichia coli (Gram-negative) within 5 min. The treated cotton fabric had greater breaking strength than those treated with the traditional process, as well as good washing stability.

Antioxidant capacity of the extracts from flowers of Erica australis L.: Comparison between microwave hydrodiffusion and gravity (MHG) and distillation extraction techniques - Formulation of sunscreen creams

Microwave hydrodiffusion and gravity (MHG) extraction of Erica australis flowers was optimized evaluating different microwave irradiation powers (25−200 W). Collected extracts were compared with the liquid phase obtained by conventional distillation. Their total phenolic content, antioxidant capacity and color features were evaluated. Microscopical properties of the flower tissues allowed assessing the distinct effects of the extraction processes. The cosmetic application of the collected bioactive extracts in the formulation of sunscreen creams with waters from three different thermal spring waters and the corresponding characterization (e.g. chemical, bioactive and rheological features) and sensory analysis were also made. For cosmetic comparative purposes, extracts from Ulex europaeus flowers obtained by MHG procedure was also analyzed. The stability of these oil-in-water model emulsions was tested during accelerated oxidation conditions. Results indicated that MHG at 50 W for 130 min was the most adequate work conditions for the extraction of antioxidant compounds from these wild flowers (around 0.27 mg Trolox eq/g flower dry weight and 0.01 mg ascorbic acid/g flower dry weight or 0.04 mg FeSO4 * 7H2O/g flower dry weight). This procedure also led a drop of energy consumption environmental impact (about 8 times less) in comparison with distillation method. Small total color differences were detected between the gathered extracts. The incorporation of flower extracts produced similar effects when compared with added commercial antioxidants except for viscous behavior. Sensorially, E. australis extract incorporated with thermal waters displayed a positive effect on the skin cream application of the formulated cosmetic, mainly with thermal water 3.

Drying of Steaming Maple Timber in Drying Kilns, While Preserving the Color Acquired by the Wood Steaming Process

The paper presents a mode for drying steaming maple timber of thickness h = 38 mm from moisture W1 = 50 % to W2 = 10 %, while preserving the color of wood obtained by the steaming process. The drying process is divided into two parts. Evaporation of free water from wet wood at drying medium temperatures td = 35 - 40 °C and evaporation of water from wood below the hygroscopicity limit W ≤ 25 % at drying medium temperatures td = 70 - 80 °C. Total color difference ΔE* determined by the difference in values on the CIE L*a*b* color space coordinates dried by the proposed mode for steaming maple timber and the reference values ΔE* = 1.03. According to the categorization of wood color changes in thermal processes by work (Cividini et al. (2007), this change belongs to the category of small color changes. A negative aspect of this drying mode is the approx. 25 % increase in timber drying time.

Bridging the ultraviolet and optical regions: Transformation equations between GALEX and UBV photometric systems

Abstract We derive transformation equations between GALEX and UBV colours by using the reliable data of 556 stars. We present two sets of equations: as a function of (only) luminosity class and as a function of both luminosity class and metallicity. The metallicities are provided from the literature, while the luminosity classes are determined by using the PARSEC mass tracks in this study. Small colour residuals and high squared correlation coefficients promise accurate derived colours. The application of the transformation equations to 70 stars with reliable data shows that the metallicity plays an important role in estimation of more accurate colours.

Study on color stability under different light sources based on color difference analysis

Product color is an important indicator to measure product quality. Since the change of the light sources in the product circulation environment cannot be avoided, the color of the product will be affected by the change of the light sources undoubtedly. Therefore, it is of practical significance to study the color stability under different light sources. D65 light source was used as the standard light source, A and F2 light sources were used as the test light sources, a large number of color blocks were chosen as samples, and the color difference of the sample under different light sources was used to measure the color stability of the sample under different light sources. Firstly, by analyzing samples with different excitation purity, it was found that there was a positive correlation between the color difference and the excitation purity; Secondly, by analyzing samples with different dominant wavelength/complementary wavelength, it was found that the color difference was related to the dominant wavelength/complementary wavelength closely. When the dominant wavelength of the sample was 479nm, ΔEab*(D65/A), ΔEab*(D65/F2) were 14.50, 13.81 respectively. When the dominant wavelength of the sample was 561nm, ΔEab*(D65/A), ΔEab*(D65/F2) were only 5.17, 2.78 respectively. After corresponding to the dominant wavelength/complementary wavelength and the hue, it showed that the samples with purple, yellow, yellow-green hue had smaller color difference under different light sources, while the samples with red, cyan, light blue hue had larger color difference. The results showed that the color stability under different light sources was related to the excitation purity and the dominant wavelength/complementary wavelength. In actual production and application, there are two ways to improve the color stability of the product under different light sources, one is to choose a color with lower excitation purity, and the other is to choose a color with purple, yellow, yellow green hue.

Color-based feature extraction with application to facial recognition using tensor-matrix and tensor-tensor analysis

In this article, two main goals are investigated. 1) Developing the capabilities of tensor analysis into machine learning and pattern recognition applications such as facial recognition. 2) Answering a controversial question about the usefulness of the color information for face recognition despite small color sub-space which facial pictures possess. Firstly, an algorithm based on merely color information, extracted by tensor-matrix decomposition, is proposed. The proposed method reveals the potential of this kind of information. Secondly, another algorithm is proposed which utilizes both color and structural information by which the recognition rate is improved. Finally, by presenting the third algorithm based on tensor-tensor analysis and introducing the Eigen-Tensor concept, the task is fulfilled. The third algorithm is able to extract the color information and accomplish the dimensionality reduction simultaneously. To validate their robustness, these three proposed algorithms are evaluated by three different databases with different properties. The results represent the capabilities of tensor-tensor analysis, in comparison with other approaches. It is also proven that in spite of using the ordinary classifiers, the recognition rate more than 94% is achievable.

Following the crumbs: statistical effects of ram pressure in galaxies

ABSTRACT We analyse the presence of dust around galaxy group members through the reddening of background quasars. By taking into account quasar colour and their dependence on redshift and angular position, we derive mean quasar colours excess in projected regions around member galaxies and infer the associated dust mass. For disc-like galaxies perpendicular to the plane of the sky, and at groupcentric distances of the order of the virial radius, thus likely to reside in the infall regions of groups, we find systematic colour excess values e ∼ 0.009 ± 0.004 for g − r colour. Under the hypothesis of Milky Way dust properties, we derive dust masses of $5.8 \pm 2.5 \times 10^8 \, \mathrm{M}_{\odot }\, h^{-1}$, implying that a large fraction of dust is being stripped from galaxies in their path to groups. We also studied the photometry of member galaxies to derive a colour asymmetry relative to the group centre direction from a given galaxy. We conclude that the regions of galaxies facing the centre are bluer, consistent with the effects of gas compression and star formation. We also combine these two procedures finding that galaxies with a small colour asymmetry show the largest amounts of dust towards the external regions compared to a control sample. We conclude that dust removal is very efficient in galaxies on infall. The fact that galaxies redder towards groups centres are associated with the strongest reddening of background quasars suggest that gas removal induced by ram pressure stripping plays a key role in galaxy evolution and dust content.

Multispectral Image Segmentation Based on a Fuzzy Clustering Algorithm Combined with Tsallis Entropy and a Gaussian Mixture Model

Accurate multispectral image segmentation is essential in remote sensing research. Traditional fuzzy clustering algorithms used to segment multispectral images have several disadvantages, including: (1) they usually only consider the pixels’ grayscale information and ignore the interaction between pixels; and, (2) they are sensitive to noise and outliers. To overcome these constraints, this study proposes a multispectral image segmentation algorithm based on fuzzy clustering combined with the Tsallis entropy and Gaussian mixture model. The algorithm uses the fuzzy Tsallis entropy as regularization item for fuzzy C-means (FCM) and improves dissimilarity measure using the negative logarithm of the Gaussian Mixture Model (GMM). The Hidden Markov Random Field (HMRF) is introduced to define prior probability of neighborhood relationship, which is used as weights of the Gaussian components. The Lagrange multiplier method is used to solve the segmentation model. To evaluate the proposed segmentation algorithm, simulated and real multispectral images were segmented using the proposed algorithm and two other algorithms for comparison (i.e., Tsallis Fuzzy C-means (TFCM), Kullback–Leibler Gaussian Fuzzy C-means (KLG-FCM)). The study found that the modified algorithm can accelerate the convergence speed, reduce the effect of noise and outliers, and accurately segment simulated images with small gray level differences with an overall accuracy of more than 98.2%. Therefore, the algorithm can be used as a feasible and effective alternative in multispectral image segmentation, particularly for those with small color differences.

First Report of Brown Apical Necrosis of Walnut Fruit Caused by Fusarium avenaceum in Hubei, China

Brown apical necrosis (BAN) is a serious disease complex of walnut (Juglans regia L.) in France, Italy, Spain, and Turkey (Moragrega and Ozaktan 2010). Since 2014, BAN has been observed in 50 to 70% of trees in over 40,000 ha of walnut orchards in Baokang County and other counties of Hubei Province, China. In the early fruit development stages, external apical necrosis was observed exclusively at the fruit stigmatic or blossom end with small lesions and brown color. The lesion enlarged up to the fruit surface, invaded and decayed the inner tissues, and premature fruit drop occurred for many trees. Sections of the fruit revealed that inner tissues contained a brown to black rot. A total of 165 symptomatic fruits (cultivar Qingxiang) were collected periodically from Baokang County from May 2016 to 2018, and 165 fungal isolates and 104 bacterial isolates were obtained from infected fruits. Among the bacterial isolates, Pantoea agglomerans was the dominant species and accounted for 45.2% (2-year average), in agreement with Yang et al. (2011). Among the fungal isolates, Fusarium avenaceum (Fr.) Sacc. was the dominant species and accounted for 28.7% (3-year avg.), and Alternaria spp. for 25.5% (3-year avg.) and Colletotrichum spp. for 24.1% (3-year avg.). The frequency of F. avenaceum isolation between diseased and healthy areas was higher than that from rotted areas, but the opposite was observed for Alternaria spp. and Colletotrichum spp. Two Fusarium isolates, JRBK-5 and JRBK-10, were characterized and identified as F. avenaceum (Leslie and Summerell 2006).The translation elongation factor 1α (TEF-1α) gene and partial β-tubulin (TUB2) gene of isolate JRBK-5 were respectively amplified and sequenced (Zhu et al. 2014). The TEF-1α sequence (GenBank accession no. KY475585) showed 99.8% identity with F. avenaceum (KP170732) and the TUB2 sequence (KY475586) showed 100% identity with F. avenaceum (EU357852). Phylogenetic analyses showed that JRBK-5 was in the same clade as other isolates of F. avenaceum with high bootstrap support over 93%. To confirm pathogenicity, F. avenaceum JRBK-5 and JRBK-10, Alternaria spp., Colletotrichum spp., and P. agglomerans (10⁸ CFU ml⁻¹) were used to inoculate the stylar end of the detached premature fruits using 5-mm-diameter mycelial plugs with a non-wound inoculation method. Controls were treated with water and a PDA plug without the fungi. All fruits were incubated in a growth chamber at 25°C and 80 to 90% RH. Six days after inoculation, brown necrotic spots appeared on the fruits inoculated with all individual species. F. avenaceum showed higher virulence than the other fungi. The lesion diameter of F. avenaceum was 25.0 ± 2.0 mm, and those of the other fungi were <9.3 ± 1.4 mm. Combinations of F. avenaceum with the other fungi resulted in brown necrotic spots and virulence was the same as F. avenaceum alone. The inner tissues of inoculated fruits turned dark brown to black with decay. However, no symptoms developed on the control fruits. Reisolated F. avenaceum had the same cultural characteristics as the originally isolated F. avenaceum. The pathogenicity tests were repeated with similar results. Based on morphological characteristics, sequence analysis of the TEF-1α and TUB2, and Koch’s postulates, the isolates JRBK-5 and JRBK-10 were identified as F. avenaceum. To our knowledge, this is the first report of F. avenaceum causing BAN disease of walnut in Hubei, China.

Effects of Kaempferia galanga L. essential oil incorporation on sensory and physical properties of dark chocolate bar

Chocolate is the world’s most popular confectionery product of processed cocoa. The antioxidant content of cocoa flavanols in dark chocolate is higher than other types of chocolate. Widely cultivated in Indonesia, kencur (Kaempferia galanga L.) rhizome has many health benefits, including antitussive, expectorant, antioxidant, and hypocholesterolemic. The aims of this research were to evaluate the effects of variation concentration of kencur (Kaempferia galanga L.) rhizomes essential oil incorporation on sensory and physical properties of dark chocolate bar. Three formulas of dark chocolate bar with an addition of Kaempferia galanga L. rhizomes essential oil (0.1%, 0.2%, and 0.3%) were studied. The results showed that the addition of variation of the essential oil concentration (0.1%, 0.2%, and 0.3%) had no significant effect on the overall sensory properties. However, dark chocolate bar with the addition of 0.3% Kaempferia galanga L. essential oil (F3) showed the highest panelist acceptance on aroma attributes. It had very small color difference and the lowest hardness based on the result of physical characterization, suggesting that dark chocolate bar with the addition of 0.3% Kaempferia galanga L. essential oil (F3) is expected to be developed as one of chocolate-based functional food products.